Creating Smooth Rounded Corners in WinForm Applications - c#

I want to create a button and a container with rounded corners.
I'm using the Region to paint the corners, code attached below.
However the corners doesn't seem smooth, is there any way to fix this, any help would be appreciated.
Image attached below as im not allowed to upload images yet.
[DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
private static extern IntPtr CreateRoundRectRgn(
int nLeftRect,
int nTopRect,
int nRightRect,
int nBottomRect,
int nWidthEllipse,
int nHeightEllipse
);
public Login()
{
InitializeComponent();
this.Region = System.Drawing.Region.FromHrgn(CreateRoundRectRgn(0, 0, Width, Height, 30, 30));
this.logo.Image = Properties.Resources.logo;
this.btn_login.Region = System.Drawing.Region.FromHrgn(CreateRoundRectRgn(0, 0, this.btn_login.Width, this.btn_login.Height, 10, 10));
}

Once the function is not implemented using the normal WinForm function.
Therefore we must implement it using win32Api.
The code is created referring to this and this.
First, you have to draw a round rectangle.
public static GraphicsPath RoundedRect(Rectangle bounds, int radius)
{
int diameter = radius * 2;
Size size = new Size(diameter, diameter);
Rectangle arc = new Rectangle(bounds.Location, size);
GraphicsPath path = new GraphicsPath();
if (radius == 0)
{
path.AddRectangle(bounds);
return path;
}
// top left arc
path.AddArc(arc, 180, 90);
// top right arc
arc.X = bounds.Right - diameter;
path.AddArc(arc, 270, 90);
// bottom right arc
arc.Y = bounds.Bottom - diameter;
path.AddArc(arc, 0, 90);
// bottom left arc
arc.X = bounds.Left;
path.AddArc(arc, 90, 90);
path.CloseFigure();
return path;
}
public static void FillRoundedRectangle(Graphics graphics, Brush brush, Rectangle bounds, int cornerRadius)
{
if (graphics == null)
throw new ArgumentNullException("graphics");
if (brush == null)
throw new ArgumentNullException("brush");
using (GraphicsPath path = RoundedRect(bounds, cornerRadius))
{
graphics.FillPath(brush, path);
}
}
And let's add it to the drawing call.
private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics graphics = e.Graphics;
Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
Brush b = new LinearGradientBrush(gradientRectangle, Color.DarkSlateBlue, Color.MediumPurple, 0.0f);
graphics.SmoothingMode = SmoothingMode.HighQuality;
FillRoundedRectangle(graphics, b, gradientRectangle, 35);
}
Then we can draw the same form as the picture above.
Second, draw a form using Per Pixel Alpha Blend.
public void SetBitmap(Bitmap bitmap)
{
SetBitmap(bitmap, 255);
}
public void SetBitmap(Bitmap bitmap, byte opacity)
{
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
throw new ApplicationException("The bitmap must be 32ppp with alpha-channel.");
IntPtr screenDc = Win32.GetDC(IntPtr.Zero);
IntPtr memDc = Win32.CreateCompatibleDC(screenDc);
IntPtr hBitmap = IntPtr.Zero;
IntPtr oldBitmap = IntPtr.Zero;
try
{
hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
oldBitmap = Win32.SelectObject(memDc, hBitmap);
Win32.Size size = new Win32.Size(bitmap.Width, bitmap.Height);
Win32.Point pointSource = new Win32.Point(0, 0);
Win32.Point topPos = new Win32.Point(Left, Top);
Win32.BLENDFUNCTION blend = new Win32.BLENDFUNCTION();
blend.BlendOp = Win32.AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = opacity;
blend.AlphaFormat = Win32.AC_SRC_ALPHA;
Win32.UpdateLayeredWindow(Handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, Win32.ULW_ALPHA);
}
finally
{
Win32.ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
Win32.SelectObject(memDc, oldBitmap);
Win32.DeleteObject(hBitmap);
}
Win32.DeleteDC(memDc);
}
}
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x00080000;
return cp;
}
}
Finally, call SetBitmap when loading a form.
private void Form1_Load(object sender, EventArgs e)
{
Bitmap myBitmap = new Bitmap(this.Width, this.Height);
Graphics graphics = Graphics.FromImage(myBitmap);
Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
Brush b = new LinearGradientBrush(gradientRectangle, Color.DarkSlateBlue, Color.MediumPurple, 0.0f);
graphics.SmoothingMode = SmoothingMode.HighQuality;
FillRoundedRectangle(graphics, b, gradientRectangle, 35);
SetBitmap(myBitmap);
}
When you finish the above tasks, you can finally get Smooth Round Corners in WinForm Applications.
Full code of Form
public class RoundedForm : Form
{
private Timer drawTimer = new Timer();
public NanoRoundedForm()
{
this.FormBorderStyle = FormBorderStyle.None;
}
protected override void OnLoad(EventArgs e)
{
if (!DesignMode)
{
drawTimer.Interval = 1000 / 60;
drawTimer.Tick += DrawForm;
drawTimer.Start();
}
base.OnLoad(e);
}
private void DrawForm(object pSender, EventArgs pE)
{
using (Bitmap backImage = new Bitmap(this.Width, this.Height))
{
using (Graphics graphics = Graphics.FromImage(backImage))
{
Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
using (Brush b = new LinearGradientBrush(gradientRectangle, Color.DarkSlateBlue, Color.MediumPurple, 0.0f))
{
graphics.SmoothingMode = SmoothingMode.HighQuality;
RoundedRectangle.FillRoundedRectangle(graphics, b, gradientRectangle, 35);
foreach (Control ctrl in this.Controls)
{
using (Bitmap bmp = new Bitmap(ctrl.Width, ctrl.Height))
{
Rectangle rect = new Rectangle(0, 0, ctrl.Width, ctrl.Height);
ctrl.DrawToBitmap(bmp, rect);
graphics.DrawImage(bmp, ctrl.Location);
}
}
PerPixelAlphaBlend.SetBitmap(backImage, Left, Top, Handle);
}
}
}
}
protected override void OnPaint(PaintEventArgs e)
{
if (DesignMode)
{
Graphics graphics = e.Graphics;
Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
Brush b = new LinearGradientBrush(gradientRectangle, Color.DarkSlateBlue, Color.MediumPurple, 0.0f);
graphics.SmoothingMode = SmoothingMode.HighQuality;
RoundedRectangle.FillRoundedRectangle(graphics, b, gradientRectangle, 35);
}
base.OnPaint(e);
}
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
if (!DesignMode)
{
cp.ExStyle |= 0x00080000;
}
return cp;
}
}
}
public static class RoundedRectangle
{
public static GraphicsPath RoundedRect(Rectangle bounds, int radius)
{
int diameter = radius * 2;
Size size = new Size(diameter, diameter);
Rectangle arc = new Rectangle(bounds.Location, size);
GraphicsPath path = new GraphicsPath();
if (radius == 0)
{
path.AddRectangle(bounds);
return path;
}
// top left arc
path.AddArc(arc, 180, 90);
// top right arc
arc.X = bounds.Right - diameter;
path.AddArc(arc, 270, 90);
// bottom right arc
arc.Y = bounds.Bottom - diameter;
path.AddArc(arc, 0, 90);
// bottom left arc
arc.X = bounds.Left;
path.AddArc(arc, 90, 90);
path.CloseFigure();
return path;
}
public static void FillRoundedRectangle(Graphics graphics, Brush brush, Rectangle bounds, int cornerRadius)
{
if (graphics == null)
throw new ArgumentNullException("graphics");
if (brush == null)
throw new ArgumentNullException("brush");
using (GraphicsPath path = RoundedRect(bounds, cornerRadius))
{
graphics.FillPath(brush, path);
}
}
}
internal static class PerPixelAlphaBlend
{
public static void SetBitmap(Bitmap bitmap, int left, int top, IntPtr handle)
{
SetBitmap(bitmap, 255, left, top, handle);
}
public static void SetBitmap(Bitmap bitmap, byte opacity, int left, int top, IntPtr handle)
{
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
throw new ApplicationException("The bitmap must be 32ppp with alpha-channel.");
IntPtr screenDc = Win32.GetDC(IntPtr.Zero);
IntPtr memDc = Win32.CreateCompatibleDC(screenDc);
IntPtr hBitmap = IntPtr.Zero;
IntPtr oldBitmap = IntPtr.Zero;
try
{
hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
oldBitmap = Win32.SelectObject(memDc, hBitmap);
Win32.Size size = new Win32.Size(bitmap.Width, bitmap.Height);
Win32.Point pointSource = new Win32.Point(0, 0);
Win32.Point topPos = new Win32.Point(left, top);
Win32.BLENDFUNCTION blend = new Win32.BLENDFUNCTION();
blend.BlendOp = Win32.AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = opacity;
blend.AlphaFormat = Win32.AC_SRC_ALPHA;
Win32.UpdateLayeredWindow(handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, Win32.ULW_ALPHA);
}
finally
{
Win32.ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
Win32.SelectObject(memDc, oldBitmap);
Win32.DeleteObject(hBitmap);
}
Win32.DeleteDC(memDc);
}
}
}
internal class Win32
{
public enum Bool
{
False = 0,
True
};
[StructLayout(LayoutKind.Sequential)]
public struct Point
{
public Int32 x;
public Int32 y;
public Point(Int32 x, Int32 y) { this.x = x; this.y = y; }
}
[StructLayout(LayoutKind.Sequential)]
public struct Size
{
public Int32 cx;
public Int32 cy;
public Size(Int32 cx, Int32 cy) { this.cx = cx; this.cy = cy; }
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct ARGB
{
public byte Blue;
public byte Green;
public byte Red;
public byte Alpha;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BLENDFUNCTION
{
public byte BlendOp;
public byte BlendFlags;
public byte SourceConstantAlpha;
public byte AlphaFormat;
}
public const Int32 ULW_COLORKEY = 0x00000001;
public const Int32 ULW_ALPHA = 0x00000002;
public const Int32 ULW_OPAQUE = 0x00000004;
public const byte AC_SRC_OVER = 0x00;
public const byte AC_SRC_ALPHA = 0x01;
[DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
public static extern Bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);
[DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
public static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("user32.dll", ExactSpelling = true)]
public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
public static extern Bool DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", ExactSpelling = true)]
public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
public static extern Bool DeleteObject(IntPtr hObject);
}

Related

Erase old lines after ControlPaint.DrawReversibleLine

I have issues on erasing old lines after ControlPaint.DrawReversibleLine and DrawReversibleFrame. I did erase, but screen (usercontrol and picturebox) retains old lines while Mouse_Move. How to erase old lines completely?
I have searched such stuff on stackoverflow, all answers are similar but no functioning for my case.
//a picturebox1 on usercontrol.
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
//...other code
ControlPaint.DrawReversibleLine(HorizontalSelectionPT1, HorizontalSelectionPT2, Color.Red); //erase old Horizontal line
ControlPaint.DrawReversibleLine(VerticalSelectionPT1, VerticalSelectionPT2, Color.Red); //erase old vertical line
Point point = PointToScreen(base.Location);
HorizontalSelectionPT1 = new Point(point.X, Cursor.Position.Y);
HorizontalSelectionPT2 = new Point(point.X + base.Width, Cursor.Position.Y);
VerticalSelectionPT1 = new Point(Cursor.Position.X, point.Y);
VerticalSelectionPT2 = new Point(Cursor.Position.X, point.Y + base.Height);
ControlPaint.DrawReversibleLine(HorizontalSelectionPT1, HorizontalSelectionPT2, Color.Red); //Draw new line
ControlPaint.DrawReversibleLine(VerticalSelectionPT1, VerticalSelectionPT2, Color.Red); //Draw new line
//draw selected frame
ControlPaint.DrawReversibleFrame(pbCanvas.RectangleToScreen(rectangle_0), Color.Black, FrameStyle.Dashed); //erase old frame
rectangle_0.Width = e.X - rectangle_0.X;
rectangle_0.Height = e.Y - rectangle_0.Y;
ControlPaint.DrawReversibleFrame(pbCanvas.RectangleToScreen(rectangle_0), Color.Black, FrameStyle.Dashed); //Draw new frame
//...other codes
}
Hardly to capture screenshot, I used Camera.
I have replaced all ControlPaint.DrawReverseFrame with GDI32 APIs to solve the erase old line problem. Whatever I tried using ControlPaint.DrawReversibleLine produced either undesired effect or flickering.
private static int ArgbToRGB(int rgb)
{
return ((rgb >> 16 & 0x0000FF) | (rgb & 0x00FF00) | (rgb << 16 & 0xFF0000));
}
public enum PenStyles
{
PS_OLID = 0,
PS_DASH = 1,
PS_DOT = 2,
PS_DASHDOT = 3,
PS_DASHDOTDOT = 4,
PS_NULL = 5,
PS_INSIDEFRAME = 6,
PS_USERSTYLE = 7,
PS_ALTERNATE = 8,
PS_STYLE_MASK = 0x0000000F,
PS_ENDCAP_ROUND = 0x00000000,
PS_ENDCAP_SQUARE = 0x00000100,
PS_ENDCAP_FLAT = 0x00000200,
PS_ENDCAP_MASK = 0x00000F00,
PS_JOIN_ROUND = 0x00000000,
PS_JOIN_BEVEL = 0x00001000,
PS_JOIN_MITER = 0x00002000,
PS_JOIN_MASK = 0x0000F000,
PS_COSMETIC = 0x00000000,
PS_GEOMETRIC = 0x00010000
PS_TYPE_MASK = 0x000F0000
}
public enum GDIDrawingMode
{
R2_BLACK = 1,
R2_NOTMERGEPEN = 2,
R2_MASKNOTPEN = 3,
R2_NOTCOPYPEN = 4,
R2_MASKPENNOT = 5,
R2_NOT = 6,
R2_XORPEN = 7,
R2_NOTMASKPEN = 8,
R2_MASKPEN = 9,
R2_NOTXORPEN = 10,
R2_NOP = 11,
R2_MERGENOTPEN = 12,
R2_COPYPEN = 13,
R2_MERGEPENNOT = 14,
R2_MERGEPEN = 15,
R2_WHITE = 16
}
[DllImport("gdi32.dll", CharSet = CharSet.Auto, EntryPoint = "Rectangle", ExactSpelling = true, SetLastError = true)]
public static extern bool GDIDrawRectangle(IntPtr hDC, int left, int top, int right, int bottom);
[DllImport("gdi32.dll")]
public static extern int SetROP2(IntPtr hDC, int fnDrawMode);
[DllImport("gdi32.dll")]
public static extern bool MoveToEx(IntPtr hDC, int x, int y, ref Point p);
[DllImport("gdi32.dll")]
public static extern bool LineTo(IntPtr hdc, int x, int y);
[DllImport("gdi32.dll")]
public static extern IntPtr CreatePen(int fnPenStyle, int nWidth, int crColor);
[DllImport("gdi32.dll")]
public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObj);
[DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObj);
public static void DrawXORRectangle(Graphics graphics, Color penColor, Rectangle rectangle)
{
IntPtr hDC = graphics.GetHdc();
IntPtr hPen = CreatePen((int)PenStyles.PS_DOT, 1, ArgbToRGB(penColor.ToArgb()));
IntPtr hOldPen = SelectObject(hDC, hPen);
SetROP2(hDC, (int)GDIDrawingMode.R2_NOTXORPEN);
GDIDrawRectangle(hDC, rectangle.Left, rectangle.Top, rectangle.Right, rectangle.Bottom);
SelectObject(hDC, hOldPen);
DeleteObject(hPen);
graphics.ReleaseHdc(hDC);
}

Bitmap gets mangled when I converted from System.Drawing.Bitmap object to cv::Mat

I have a WPF application that takes a screen shot of the running Handbrake executable using a class called ScreenCapture that I copied from stack overflow.
public class ScreenCapture
{
[DllImport("user32.dll")]
static extern int GetWindowRgn(IntPtr hWnd, IntPtr hRgn);
//Region Flags - The return value specifies the type of the region that the function obtains. It can be one of the following values.
const int ERROR = 0;
const int NULLREGION = 1;
const int SIMPLEREGION = 2;
const int COMPLEXREGION = 3;
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GetWindowRect(HandleRef hWnd, out RECT lpRect);
[DllImport("gdi32.dll")]
static extern IntPtr CreateRectRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect);
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool PrintWindow(IntPtr hwnd, IntPtr hDC, uint nFlags);
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left, Top, Right, Bottom;
public RECT(int left, int top, int right, int bottom)
{
Left = left;
Top = top;
Right = right;
Bottom = bottom;
}
public RECT(System.Drawing.Rectangle r) : this(r.Left, r.Top, r.Right, r.Bottom) { }
public int X
{
get { return Left; }
set { Right -= (Left - value); Left = value; }
}
public int Y
{
get { return Top; }
set { Bottom -= (Top - value); Top = value; }
}
public int Height
{
get { return Bottom - Top; }
set { Bottom = value + Top; }
}
public int Width
{
get { return Right - Left; }
set { Right = value + Left; }
}
public System.Drawing.Point Location
{
get { return new System.Drawing.Point(Left, Top); }
set { X = value.X; Y = value.Y; }
}
public System.Drawing.Size Size
{
get { return new System.Drawing.Size(Width, Height); }
set { Width = value.Width; Height = value.Height; }
}
public static implicit operator System.Drawing.Rectangle(RECT r)
{
return new System.Drawing.Rectangle(r.Left, r.Top, r.Width, r.Height);
}
public static implicit operator RECT(System.Drawing.Rectangle r)
{
return new RECT(r);
}
public static bool operator ==(RECT r1, RECT r2)
{
return r1.Equals(r2);
}
public static bool operator !=(RECT r1, RECT r2)
{
return !r1.Equals(r2);
}
public bool Equals(RECT r)
{
return r.Left == Left && r.Top == Top && r.Right == Right && r.Bottom == Bottom;
}
public override bool Equals(object obj)
{
if (obj is RECT)
return Equals((RECT)obj);
else if (obj is System.Drawing.Rectangle)
return Equals(new RECT((System.Drawing.Rectangle)obj));
return false;
}
public override int GetHashCode()
{
return ((System.Drawing.Rectangle)this).GetHashCode();
}
public override string ToString()
{
return string.Format(System.Globalization.CultureInfo.CurrentCulture, "{{Left={0},Top={1},Right={2},Bottom={3}}}", Left, Top, Right, Bottom);
}
}
public Bitmap GetScreenshot(IntPtr ihandle)
{
IntPtr hwnd = ihandle;//handle here
RECT rc;
GetWindowRect(new HandleRef(null, hwnd), out rc);
Bitmap bmp = new Bitmap(rc.Right - rc.Left, rc.Bottom - rc.Top, PixelFormat.Format32bppArgb);
Graphics gfxBmp = Graphics.FromImage(bmp);
IntPtr hdcBitmap;
try
{
hdcBitmap = gfxBmp.GetHdc();
}
catch
{
return null;
}
bool succeeded = PrintWindow(hwnd, hdcBitmap, 0);
gfxBmp.ReleaseHdc(hdcBitmap);
if (!succeeded)
{
gfxBmp.FillRectangle(new SolidBrush(Color.Gray), new Rectangle(Point.Empty, bmp.Size));
}
IntPtr hRgn = CreateRectRgn(0, 0, 0, 0);
GetWindowRgn(hwnd, hRgn);
Region region = Region.FromHrgn(hRgn);//err here once
if (!region.IsEmpty(gfxBmp))
{
gfxBmp.ExcludeClip(region);
gfxBmp.Clear(Color.Transparent);
}
gfxBmp.Dispose();
return bmp;
}
public void WriteBitmapToFile(string filename, Bitmap bitmap)
{
bitmap.Save(filename, ImageFormat.Bmp);
}
So when the button click handler below is called a screenshot of the handbrake window is taken.
I write it to the harddrive to make sure its ok:
handbrake screen shot.
I create an instance of a CLR class library ClassLibrary1::Class1 and call the method "DoSomething" passing it the System.Drawing.Bitmap object.
private void button4_Click(object sender, RoutedEventArgs e)
{
string wName = "HandBrake";
IntPtr hWnd = IntPtr.Zero;
foreach (Process pList in Process.GetProcesses())
{
if (pList.MainWindowTitle.Contains(wName))
{
hWnd = pList.MainWindowHandle;
var sc = new ScreenCapture();
SetForegroundWindow(hWnd);
var bitmap = sc.GetScreenshot(hWnd);
sc.WriteBitmapToFile("handbrake.bmp", bitmap);
Bitmap image1 = (Bitmap)System.Drawing.Image.FromFile("handbrake.bmp", true);
ClassLibrary1.Class1 opencv = new ClassLibrary1.Class1();
opencv.DoSomething(image1);
}
}
}
Inside DoSomething I attempt to convert the System.Drawing.Bitmap to a OpenCV class cv::Mat. I call cv::imwrite to make sure the bitmap is still ok, unfortunately somethings gone wrong: mangled handbrake screenshot
void Class1::DoSomething(Bitmap ^mybitmap)
{
cv::Mat *imgOriginal;
// Lock the bitmap's bits.
Rectangle rect = Rectangle(0, 0, mybitmap->Width, mybitmap->Height);
Imaging::BitmapData^ bmpData = mybitmap->LockBits(rect, Imaging::ImageLockMode::ReadWrite, mybitmap->PixelFormat);
try
{
// Get the address of the first line.
IntPtr ptr = bmpData->Scan0;
// Declare an array to hold the bytes of the bitmap.
// This code is specific to a bitmap with 24 bits per pixels.
int bytes = Math::Abs(bmpData->Stride) * mybitmap->Height;
array<Byte>^rgbValues = gcnew array<Byte>(bytes);
// Copy the RGB values into the array.
System::Runtime::InteropServices::Marshal::Copy(ptr, rgbValues, 0, bytes);
imgOriginal = new cv::Mat(mybitmap->Height, mybitmap->Width, CV_8UC3, (void *)ptr, std::abs(bmpData->Stride));
}
finally { mybitmap->UnlockBits(bmpData); }//Remember to unlock!!!
cv::imwrite("from_mat.bmp", *imgOriginal);
}
Can anybody spot my error?
Since your image is stretched horizontally, I'm betting that you have the wrong pixel format selected. (It's not stretched vertically, nor skewed diagonally, so the stride is correct.) CV_8UC3 specifies 24 bits per pixel, but I think that your BMP file is using 32 bits per pixel.
Switch your pixel format to CV_8UC4, or better yet, read the number of bits per pixel from the image and select the correct CV format based on that.
Side note: Since you're doing sc.WriteBitmapToFile() followed by opencv.DoSomething(Image.FromFile(), the entire bit about how you're capturing the screenshot is irrelevant. You're reading the bitmap from a file; that's all that matters.

Graphics.MeasureString() - Finding the relative X,Y coordinates

I am attempting to create a custom ListBox control in WinForms.
I have subclassed it, set DrawMode.OwnerDrawFixed, and am overriding OnDrawItem. I have created a custom ColoredListBoxItem class that has additional properties to deal with the highlighting.
This is all fine. My issue is that this functionality needs to highlight words within the text of a list item.
Here is as far as I've gotten, and it doesn't work, because the X coordinate of the highlight remains constant and does not correspond to the actual X coordinate of the text.
How can I get a Point value (or Rectangle) to use with DrawText that will overlay the highlighted text? I've tried doing some math with the bounds of the original text Rectangle versus the highlight Rectangle but it is not working as expected.
protected override void OnDrawItem(DrawItemEventArgs e) {
ColoredListBoxItem item = this.Items[e.Index] as ColoredListBoxItem;
e.DrawBackground();
e.DrawFocusRectangle();
Rectangle fullMessageRect = e.Bounds;
// Draw the original, full text
TextRenderer.DrawText(e.Graphics, item.Message, e.Font,
new Point(fullMessageRect.X, fullMessageRect.Y),
this.ForeColor);
// Check if we have any text to be highlighted
if (SomethingToHighlight(item)) {
// Find the text to highlight, and get its area
SizeF highlightedAreaSize =
e.Graphics.MeasureString(item.TextToHightlight, e.Font);
PointF highlightAreaPoint = highlightedAreaSize.ToPointF();
Point point = new Point(Convert.ToInt32(highlightAreaPoint.X),
Convert.ToInt32(fullMessageRect.Y));
TextRenderer.DrawText(e.Graphics, item.TextToHightlight, e.Font,
point, this.ForeColor, item.HighlightColor);
}
}
Here is what I'm seeing in a demo app, where the output just shows work being done, and I am trying to highlight one particular word .. in this case "height".
Don't pay any attention to the actual output, it's a bunch of nonsense so I can see exactly how another part of the system is adjusting PictureBox images on the fly.
Lines that it thinks should be highlighted are shown twice, once in the original format and then again with the highlight applied. Notice how the highlighted part is correct in the Y coordinate, but does not change in the X.
Here's what I am seeing in the Watch window when I set a break point prior to writing the highlighted text:
Clearly, I don't need the variable highlightAreaPoint, because it's the same as highlightedAreaSize.
Probably something obvious here but I'm tired of fiddling with it at this point!
I can feel your pain as I have been there before. Actually, I wanted to design my own Textbox not inheriting from Microsoft.Textbox control and when I researched on-line, I sort of discouraged to learn 1000 reasons why one must not reinvent the wheel and why it is so difficult to do from scratch. Highlighting selection text was one of the major challenge among the others like right-to-left, caret positioning, non-fixed fonts etc. But I decided to fly against the wind because I had my reasons to do so and finally got what I wanted. Since my text selection code was for TextBox, I had to change it to suit your requirement as you are dealing with ListBox.
Following is the code snippet:
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace HowToHighlightPortionOfText
{
public static class Helper
{
private static Rectangle dummy
{
get
{
return new Rectangle(0, 0, 10, 10);
}
}
const uint H = 0x00000000;
const uint V = 0x00000001;
const uint T = 0x00000002;
#region api functions
[DllImport("user32.dll")]
static extern int DrawText(IntPtr hdc, string lpStr, int nCount, ref Dimension lpRect, int wFormat);
[DllImport("gdi32.dll")]
public static extern IntPtr SelectObject(this IntPtr hdc, IntPtr hObject);
[DllImport("gdi32.dll")]
public static extern int DeleteObject(this IntPtr hObject);
[DllImport("gdi32.dll", EntryPoint = "GdiGradientFill", ExactSpelling = true)]
static extern bool GradientFill(IntPtr hdc, Trivertex[] pVertex,
uint dwNumVertex, uint[] pMesh, uint dwNumMesh, uint dwMode);
[DllImport("gdi32")]
public static extern int SetBkMode(this IntPtr hdc, int nBkMode);
[DllImport("gdi32.dll")]
public static extern uint SetTextColor(this IntPtr hdc, int crColor);
[DllImport("gdi32.dll")]
public static extern uint SetBkColor(this IntPtr hdc, int crColor);
#endregion
#region public methods
//use this function to hilight portion of listbox item text
public static void HilightItemText(this ListBox control, int itemIndex, int startIndex, int endIndex,
Color highlightForeColor, Color highlightBackColorStart, Color? highlightBackColorEnd = null)
{
var container = control.GetItemRectangle(itemIndex);
var text = control.GetItemText(itemIndex);
using (Graphics g = control.CreateGraphics())
{
g.HighlightText(control.Font, text, container, startIndex, endIndex,
highlightForeColor, highlightBackColorStart, highlightBackColorEnd);
}
}
public static void HighlightText(this IDeviceContext dc, Font font, string text,
Rectangle container, int start, int end, Color highlightForeColor, Color highlightBackColorStart,
Color? highlightBackColorEnd, DrawTextFlags? flags = null)
{
IntPtr hdc = dc.GetHdc();
IntPtr _font = SelectObject(hdc, font.ToHfont());
Dimension dm = container;
var flag = flags.getMeasureFlag(false);
SetBkMode(hdc, ColorTranslator.ToWin32(Color.Transparent));
//first draw whole text
DrawText(hdc, text, text.Length, ref dm, 0);
//now get the highlight rectangle which will draw the highlighted text
Rectangle textBound, uptoIndex;
var rect = hdc.rangeBound(text, container, start, end, out textBound, out uptoIndex, flags: flags);
dm = rect;
var _backColorEnd = highlightBackColorEnd ?? highlightBackColorStart;
hdc.Fill(rect, highlightBackColorStart, _backColorEnd, Angle.A0);
SetTextColor(hdc, ColorTranslator.ToWin32(highlightForeColor));
if (start < 0 || start > text.Length - 1 || end < 0 || end > text.Length - 1)
throw new Exception("start and end value must be with in text length");
var _text = text.Substring(start, end - start + 1);
DrawText(hdc, _text, _text.Length, ref dm, 0);
DeleteObject(SelectObject(hdc, _font));
dc.ReleaseHdc();
}
public static Rectangle RangeBound(this IDeviceContext dc, Font font, string text,
Rectangle container, int start, int end, DrawTextFlags? flags = null)
{
Rectangle textBound, uptoIndex;
return dc.RangeBound(font, text, container, start, end, out textBound, out uptoIndex, flags);
}
public static Rectangle GetPortionRectangleToHighlight(this ListBox control, int itemIndex, int startIndex, int endIndex)
{
var container = control.GetItemRectangle(itemIndex);
var text = control.GetItemText(itemIndex);
Rectangle rect;
using (Graphics g = control.CreateGraphics())
{
rect = g.RangeBound(control.Font, text, container, startIndex, endIndex);
}
return rect;
}
public static bool Fill(this IntPtr hdc, Rectangle rc, Color c1,
Color c2, Angle angle)
{
return hdc.Fill(rc.X, rc.Y, rc.Right, rc.Bottom, c1, c2, angle);
}
public static bool Fill(this IntPtr hdc, int x0, int y0, int x1, int y1, Color c1, Color c2, Angle angle)
{
Trivertex[] t = new Trivertex[4]
{
new Trivertex(x0, y0, c1),
new Trivertex(x1, y1, c2),
new Trivertex(x0, y1, c1, c2),
new Trivertex(x1, y0, c1, c2)
};
uint[] pMesh = new uint[] { 0, 1, 2, 0, 1, 3 };
switch ((int)angle % 180)
{
case 0:
return GradientFill(hdc, t, 2, pMesh, 1, H);
case 45:
return GradientFill(hdc, t, 4, pMesh, 2, T);
case 90:
return GradientFill(hdc, t, 2, pMesh, 1, V);
case 135:
t[0].x = x1;
t[3].x = x0;
t[1].x = x0;
t[2].x = x1;
return GradientFill(hdc, t, 4, pMesh, 2, T);
default:
return false;
}
}
#endregion
#region get the highlight rectangle
static Rectangle RangeBound(this IDeviceContext dc, Font font, string text,
Rectangle container, int start, int end, out Rectangle textBound, out Rectangle uptoIndex, DrawTextFlags? flags = null)
{
textBound = Rectangle.Empty;
uptoIndex = Rectangle.Empty;
if (string.IsNullOrEmpty(text)) return Rectangle.Empty;
IntPtr hdc = dc.GetHdc();
IntPtr _font = SelectObject(hdc, font.ToHfont());
var rc = hdc.rangeBound(text, container, start, end, out textBound, out uptoIndex, flags: flags);
DeleteObject(SelectObject(hdc, _font));
dc.ReleaseHdc();
return rc;
}
static TextMeasurement charRectangle(this IntPtr hdc, string text, Rectangle container,
string wholeText = null, Point? point = null, bool adjustByPoint = false, DrawTextFlags? flags = null)
{
if (string.IsNullOrEmpty(text)) return TextMeasurement.Default;
TextMeasurement measurement = new TextMeasurement();
Rectangle textBound;
wholeText = (wholeText ?? text);
var location = container.Location;
var measureWholeText = point == null;
measurement.UserPoint = point ?? Point.Empty;
textBound = hdc.textBound(wholeText, container, flags: flags);
var rect = textBound;
var p = point ?? new Point(container.Right, container.Y);
if (!measureWholeText)
{
if (p.X > textBound.Right)
p.X = textBound.Right;
else if (p.X < textBound.Left)
p.X = textBound.X;
}
var charIndex = 0;
var result = hdc.charRectangle(text, ref p, rect, flags, measureWholeText);
charIndex = Math.Max(0, result.Item2);
var rectangles = result.Item1;
measurement.Bounds = rectangles[0];
measurement.TextBounds = (measureWholeText) ? rectangles[1] : textBound;
rectangles[1] = measurement.TextBounds;
if (!measureWholeText && adjustByPoint && charIndex > 0)
{
float middle = (float)measurement.Bounds.Left +
measurement.Bounds.Width / 2;
if (p.X > middle - 1)
{
Rectangle r;
Dimension r1 = measurement.TextBounds;
var newresult = hdc.charBound(text, charIndex + 2, ref r1,
(int)flags.getMeasureFlag(false), out r);
if (!newresult.Equals(measurement.Bounds) &&
newresult.X > measurement.Bounds.X)
{
charIndex++;
measurement.Bounds = newresult;
}
}
}
if (measurement.Bounds.Size.Width<=0)
measurement.Bounds = new Rectangle(measurement.Bounds.Location, new Size(2, 2));
measurement.CharIndex = charIndex;
measurement.Char = '\0';
measurement.Char = text[Math.Min(charIndex, text.Length - 1)];
return measurement;
}
static Tuple<Rectangle[], int> charRectangle(this IntPtr hdc, string text, ref Point p, Rectangle rect,
DrawTextFlags? flags, bool measureWholeText = false)
{
int i = 0;
int middle = text.Length / 2, start = 0;
bool first = true;
do
{
var upto = hdc.Measure(text.Substring(0, middle), null, rect, flags);
bool found = upto.Has(p);
if (!found)
{
start = middle;
middle += (text.Length - middle) / 2;
first = false;
if (start == middle) break;
}
else break;
} while (middle > 1 && text.Length - middle > 1);
if (first)
{
return hdc.charRectangle(text.Substring(0, middle),
ref p, rect, flags);
}
else
{
Rectangle[] list = new Rectangle[2];
for (i = start; i <= middle; i++)
{
if (hdc.Measure(text, out list, p, i + 1, rect, flags))
break;
}
i = Math.Max(i, 0);
return new Tuple<Rectangle[], int>(list, i);
}
}
static Rectangle charBound(this IntPtr hdc, string text, int len,
ref Dimension bounds, int flag, out Rectangle whole)
{
DrawText(hdc, text, len, ref bounds, flag);
whole = bounds;
var rc = bounds;
if (len - 1 > 0 && len <= text.Length)
{
DrawText(hdc, text.Substring(0, len - 1), len - 1, ref rc, flag);
rc = Rectangle.FromLTRB(rc.Right, bounds.Top, bounds.Right, bounds.Bottom);
}
return rc;
}
static Rectangle rangeBound(this IntPtr hdc, string text, Rectangle container, int start, int end,
out Rectangle textBound, out Rectangle uptoIndex, DrawTextFlags? flags = null)
{
textBound = Rectangle.Empty;
uptoIndex = Rectangle.Empty;
if (string.IsNullOrEmpty(text)) return Rectangle.Empty;
var location = container.Location;
textBound = hdc.textBound(text, container, flags);
Dimension rect = textBound;
var flag = flags.getMeasureFlag(false);
start++;
var text1 = text.Substring(0, start);
var rc = hdc.charBound(text1, text1.Length, ref rect, (int)flag, out uptoIndex);
end++;
var text2 = text.Substring(0, end);
DrawText(hdc, text2, text2.Length, ref rect, (int)flag);
return Rectangle.FromLTRB(rc.Left, rect.Top, rect.Right, rect.Bottom);
}
static Rectangle textBound(this IntPtr hdc, string text, Rectangle container, DrawTextFlags? flags = null)
{
Rectangle rc = Rectangle.Empty;
if (string.IsNullOrEmpty(text)) return rc;
Point p = container.Location;
var r = hdc.Measure(text, text.Length, flags: flags);
return new Rectangle(p, r.Size);
}
static DrawTextFlags getMeasureFlag(this DrawTextFlags? flags, bool textboxControl = false)
{
DrawTextFlags flag = DrawTextFlags.CalculateArea;
if (flags != null) flag |= flags.Value;
flag |= DrawTextFlags.WordBreak | DrawTextFlags.NoPrefix
| DrawTextFlags.NoPadding | DrawTextFlags.NoClipping;
if (textboxControl) flag |= DrawTextFlags.TextBoxControl;
else flag |= DrawTextFlags.SingleLine;
return flag;
}
static Rectangle RangeBound(this IntPtr hdc, string text,
Rectangle container, int start, int end, DrawTextFlags? flags = null)
{
Rectangle textBound, uptoIndex;
return hdc.rangeBound(text, container, start, end, out textBound, out uptoIndex, flags);
}
static Rectangle Measure(this IntPtr hdc, string text, int? length = null,
Rectangle? rect = null, DrawTextFlags? flags = null)
{
if (string.IsNullOrEmpty(text)) return Rectangle.Empty;
Dimension bounds = rect ?? dummy;
var len = length ?? text.Length;
var flag = flags.getMeasureFlag(false);
var i = DrawText(hdc, text, len, ref bounds, (int)flag);
return bounds;
}
static bool Measure(this IntPtr hdc, string text, out Rectangle[] rectangles, Point p,
int? length = null, Rectangle? rect = null, DrawTextFlags? flags = null)
{
rectangles = new Rectangle[2];
if (string.IsNullOrEmpty(text)) return true;
Dimension bounds = rect ?? dummy;
var len = length ?? text.Length;
var flag = flags.getMeasureFlag(false);
Rectangle rc, rc1;
rc1 = hdc.charBound(text, len, ref bounds, (int)flag, out rc);
rectangles = new Rectangle[] { rc1, rc };
return (rectangles[0].Left < bounds.Left || rectangles[0].Has(p.X));
}
static bool Has(this Rectangle rect, int x = -1,
int y = -1, int checkRightUpto = -1, int checkBottomUpto = -1)
{
if (x == -1 && y == -1)
{
x = 0;
y = 0;
}
else
{
x = x == -1 ? rect.X : x;
y = y == -1 ? rect.Y : y;
}
if (checkRightUpto == -1)
{
checkRightUpto = rect.Width;
}
if (checkBottomUpto == -1)
{
checkBottomUpto = rect.Height;
}
return x >= rect.Left && x <= rect.Left +
checkRightUpto && y >= rect.Top &&
y <= rect.Top + checkBottomUpto;
}
static bool Has(this Rectangle rect, Point p,
int checkRightUpto = -1, int checkBottomUpto = -1)
{
return rect.Has(p.X, p.Y, checkRightUpto, checkBottomUpto);
}
#endregion
}
#region structs
[StructLayout(LayoutKind.Sequential)]
public struct Dimension
{
public int Left, Top, Right, Bottom;
public Dimension(int left, int top, int right, int bottom)
{
this.Left = left;
this.Right = right;
this.Top = top;
this.Bottom = bottom;
}
public Dimension(Rectangle r)
{
this.Left = r.Left;
this.Top = r.Top;
this.Bottom = r.Bottom;
this.Right = r.Right;
}
public static implicit operator Rectangle(Dimension rc)
{
return Rectangle.FromLTRB(rc.Left, rc.Top, rc.Right, rc.Bottom);
}
public static implicit operator Dimension(Rectangle rc)
{
return new Dimension(rc);
}
public static Dimension Default
{
get { return new Dimension(0, 0, 1, 1); }
}
}
[StructLayout(LayoutKind.Sequential)]
public struct Trivertex
{
public int x;
public int y;
public ushort Red;
public ushort Green;
public ushort Blue;
public ushort Alpha;
public Trivertex(int x, int y, Color color)
: this(x, y, color.R, color.G, color.B, color.A)
{
}
public Trivertex(int x, int y, Color color, Color other)
: this(x, y, color.R, color.G, color.B, color.A, other)
{
}
public Trivertex(int x, int y, ushort red, ushort green, ushort blue, ushort alpha)
{
this.x = x;
this.y = y;
Red = (ushort)(red << 8);
Green = (ushort)(green << 8);
Blue = (ushort)(blue << 8);
Alpha = (ushort)(alpha << 8);
}
public Trivertex(int x, int y, ushort red, ushort green, ushort blue, ushort alpha, Color other)
{
this.x = x;
this.y = y;
Red = (ushort)((red + other.R / 2) << 8);
Green = (ushort)((green + other.G / 2) << 8);
Blue = (ushort)((blue + other.B / 2) << 8);
Alpha = (ushort)((alpha + other.A / 2) << 8);
}
public static ushort R(Color c)
{
return (ushort)(c.R << 8);
}
public static ushort G(Color c)
{
return (ushort)(c.G << 8);
}
public static ushort B(Color c)
{
return (ushort)(c.B << 8);
}
public static ushort R(Color c, Color c1)
{
return (ushort)(((c.R + c1.R / 2)) << 8);
}
public static ushort G(Color c, Color c1)
{
return (ushort)(((c.G + c1.G / 2)) << 8);
}
public static ushort B(Color c, Color c1)
{
return (ushort)(((c.B + c1.B / 2)) << 8);
}
}
#endregion
#region textmeasurement interface + class
public interface ITextMeasurement : ICloneable
{
int CharIndex { get; set; }
int PreviousIndex { get; }
Rectangle Bounds { get; }
Rectangle TextBounds { get; }
char Char { get; }
Point UserPoint { get; }
void CopyFrom(ITextMeasurement other);
}
public class TextMeasurement : ITextMeasurement
{
Rectangle now, textBound;
public virtual Rectangle Bounds
{
get
{
return now;
}
set { now = value; }
}
public virtual Rectangle TextBounds
{
get
{
return textBound; ;
}
set { textBound = value; }
}
public virtual int CharIndex { get; set; }
public virtual int PreviousIndex { get; set; }
public virtual char Char { get; set; }
public Point UserPoint { get; set; }
public virtual void CopyFrom(ITextMeasurement tm)
{
PreviousIndex = tm.PreviousIndex;
CharIndex = tm.CharIndex;
Bounds = tm.Bounds;
Char = tm.Char;
TextBounds = tm.TextBounds;
UserPoint = tm.UserPoint;
if (UserPoint.IsEmpty) UserPoint = Bounds.Location;
}
public virtual object Clone()
{
var tm = new TextMeasurement();
tm.CopyFrom(this);
return tm;
}
protected virtual void ResetBounds(Point p)
{
ResetBounds(p.X, p.Y);
}
protected virtual void ResetBounds(int? lineX = null, int? lineY = null)
{
if (lineX.HasValue)
{
now.X = lineX.Value;
textBound.X = lineX.Value;
}
if (lineY.HasValue)
{
now.Y = lineY.Value;
textBound.Y = lineY.Value;
}
}
protected virtual void ResetEmptyBounds(Rectangle rc)
{
now = rc;
textBound = rc;
}
public static TextMeasurement Default
{
get { return new TextMeasurement(); }
}
}
#endregion
#region enums
public enum DrawTextFlags
{
CalculateArea = 0x00000400,
WordBreak = 0x00000010,
TextBoxControl = 0x00002000,
Top = 0x00000000,
Left = 0x00000000,
HorizontalCenter = 0x00000001,
Right = 0x00000002,
VerticalCenter = 0x00000004,
Bottom = 0x00000008,
SingleLine = 0x00000020,
ExpandTabs = 0x00000040,
TabStop = 0x00000080,
NoClipping = 0x00000100,
ExternalLeading = 0x00000200,
NoPrefix = 0x00000800,
Internal = 0x00001000,
PathEllipsis = 0x00004000,
EndEllipsis = 0x00008000,
WordEllipsis = 0x00040000,
ModifyString = 0x00010000,
RightToLeft = 0x00020000,
NoFullWidthCharacterBreak = 0x00080000,
HidePrefix = 0x00100000,
PrefixOnly = 0x00200000,
NoPadding = 0x10000000,
}
public enum Angle
{
A0 = 0,
A45 = 45,
A90 = 90,
A135 = 135,
A180 = 180
}
#endregion
}
Suppose your ItemText at index 2 is "StackOverFlow is a wonderful site" and you want to highlight "StackOverFlow" then your startIndex =0 and endIndex = 12.
To highlight portion of text use HighlightItemText method:
listBox.HilightItemText(2, 0, 12, Color.Black, Color.Gold, Color.Yellow);
To get highlighted coordinates use GetPortionRectangleToHighlight method to get co-ordinates of text portion to highlight. Please note that you just need to pass start and end index as well of portion text.
so call the function like:
var portionRectangle = listBox1.GetPortionRectangleToHighlight (2, 0, 12);
Have a look at the attached image as working proof of concept.
A simple example would be something like this:
private string[] _sentences = {
"Old height on pictureOne: 766",
"New height on pictureOne: 900",
"",
"Forcing width on objectX"
};
private void Form1Paint(object sender, PaintEventArgs e) {
int y = 10; //Start position
int x;
foreach (string s in _sentences) {
x = 0; //Start position
foreach (string word in s.Split(' ')) {
if (ShouldHeighlightWord(word)) {
e.Graphics.DrawString(word + " ", this.Font, new SolidBrush(Color.Red), x, y);
}
else {
e.Graphics.DrawString(word + " ", this.Font, new SolidBrush(Color.Black), x, y);
}
x += (int)e.Graphics.MeasureString(word + " ", this.Font).Width;
}
y += (int)Math.Ceiling(e.Graphics.MeasureString("I", this.Font).Height);
}
}
private bool ShouldHeighlightWord(string word) {
switch (word) {
case "on":
case "Old":
return true;
default:
return false;
}
}
This code is just drawing the strings onto an empty form and instead of highlighting it just changes the color to Red.
But i think you understand what i mean.
Since i dont have more code its hard to make a better example for you.
When you check:
if (SomethingToHighlight(item)) {
That only returns true/false i guess and you need something that returns all words to be highlighted, but since a word can occur twice (or more) in one sentence you need to be able to get a position in the string as well. Or just take one word at a time and check if it should be highlighted or not and then draw it to the control.

How do I detect the color of a certain pixel?

I want to make a system that can detect the color of a certain pixel that is selected.
Color[] pixelData;
pixelData= new Color[graphics.GraphicsDevice.Viewport.Width * (graphics.GraphicsDevice.Viewport.Height)];
Terrain.GetData(pixelData);
Now I want to do something like this
if(pixelData[graphics.GraphicsDevice.Viewport.Width * playervec.Y + playervec.X].R == 255)
{
rest of the code
}
But I don't know how I should do the part where it picks a certain pixel
This may help you
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using System.Diagnostics;
namespace FormTest
{
public partial class Form1 : Form
{
[DllImport("user32.dll")]
static extern bool GetCursorPos(ref Point lpPoint);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
public static extern int BitBlt(IntPtr hDC, int x, int y, int nWidth, int nHeight, IntPtr hSrcDC, int xSrc, int ySrc, int dwRop);
public Form1()
{
InitializeComponent();
}
private void MouseMoveTimer_Tick(object sender, EventArgs e)
{
Point cursor = new Point();
GetCursorPos(ref cursor);
var c = GetColorAt(cursor);
this.BackColor = c;
if (c.R == c.G && c.G < 64 && c.B > 128)
{
MessageBox.Show("Blue");
}
}
Bitmap screenPixel = new Bitmap(1, 1, PixelFormat.Format32bppArgb);
public Color GetColorAt(Point location)
{
using (Graphics gdest = Graphics.FromImage(screenPixel))
{
using (Graphics gsrc = Graphics.FromHwnd(IntPtr.Zero))
{
IntPtr hSrcDC = gsrc.GetHdc();
IntPtr hDC = gdest.GetHdc();
int retval = BitBlt(hDC, 0, 0, 1, 1, hSrcDC, location.X, location.Y, (int)CopyPixelOperation.SourceCopy);
gdest.ReleaseHdc();
gsrc.ReleaseHdc();
}
}
return screenPixel.GetPixel(0, 0);
}
}
}
EDIT:
Given the above GetColorAt function you can poll a certain pixel on the screen in a safe, performance friendly way like this:
private void PollPixel(Point location, Color color)
{
while(true)
{
var c = GetColorAt(location);
if (c.R == color.R && c.G == color.G && c.B == color.B)
{
DoAction();
return;
}
// By calling Thread.Sleep() without a parameter, we are signaling to the
// operating system that we only want to sleep long enough for other
// applications. As soon as the other apps yield their CPU time, we will
// regain control.
Thread.Sleep()
}
}
Source : How to read the Color of a Screen Pixel

VisualStyleRenderer to bitmap

I need to draw a different progress bar through VisualStyleRenderer. Everything works fine if I use Graphics of OnPaint method. But since I want to save it in hard drive, I need to render progressbar in Bitmap object and then save it.
Here is example code
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawImage(RenderProgressbarImage(), new Point(5, 5));
//following code works good
progressRenderer.SetParameters("PROGRESS", 11, 2);
progressRenderer.DrawBackground(e.Graphics, new Rectangle(125, 5, 100, 13));
}
VisualStyleRenderer progressRenderer = new VisualStyleRenderer(VisualStyleElement.ProgressBar.Bar.Normal);
Bitmap RenderProgressbarImage()
{
Bitmap bmp = new Bitmap(100, 13);
using (Graphics g = Graphics.FromImage((Image)bmp))
{
progressRenderer.SetParameters("PROGRESS", 11, 2);
progressRenderer.DrawBackground(g, new Rectangle(0, 0, bmp.Width, bmp.Height));
}
return bmp;
}
But if I draw it in Bitmap, it have black corners instead of transparent. However if it uses Graphics of OnPaint, everything draws good.
Using Bitmap, you will a rectangular object using GDI+ the way you are doing it.
Creating an Image with Rounded Corners might help you with creating a rounded bitmap image as you'd like.
Edit - Modified RenderProgressbarImage to take a Graphics object as an input
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawImage(RenderProgressbarImage(e.Graphics), new Point(5, 5));
//Test to Check for Output
RenderProgressbarImage(e.Graphics).Save(#"C:\Bitmap.bmp");;
//following code works good
progressRenderer.SetParameters("PROGRESS", 11, 2);
progressRenderer.DrawBackground(e.Graphics, new Rectangle(125, 5, 100, 13));
}
Bitmap RenderProgressbarImage(Graphics g)
{
Bitmap bmp = new Bitmap(100, 13, g);
progressRenderer.SetParameters("PROGRESS", 11, 2);
progressRenderer.DrawBackground(g, new Rectangle(0, 0, bmp.Width, bmp.Height));
return bmp;
}
Edit2: Modified to simplify solution per OP's comment below
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
Bitmap bmp = new Bitmap(100, 13, e.Graphics);
bmp.Save(<SomefilePath.png>);
//following code works good
progressRenderer.SetParameters("PROGRESS", 11, 2);
progressRenderer.DrawBackground(e.Graphics, new Rectangle(125, 5, 100, 13));
}
A note on this: doing a save of the Bitmap in the OnPaint event will be a definite performance hit on rendering. Perhaps just update a Bitmap variable in your class and save the Bitmap periodically from a different Thread/ some Timer/etc.; it all depends on your needs.
I know it's old but I faced the same problem and after a lot of research I found a solution, I hope it's help someone.
// Created by: Motaz Alnuweiri
// Reference:
// URL1: https://www.autoitscript.com/forum/topic/181956-drawthemebackground-bitmap-alpha/
// URL2: https://gist.github.com/wavescholar/11297223#file-gdi-bitmap-conversion-L71
// URL3: https://www.experts-exchange.com/questions/20872978/BITMAPINFOHEADER-from-NET-Bitmap.html
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
public class Helper
{
#region Win32 Native APIs
internal class NativeMethods
{
// CreateDIBSection funcation iUsage value
internal const int DIB_RGB_COLORS = 0x00;
internal const int DIB_PAL_COLORS = 0x01;
internal const int DIB_PAL_INDICES = 0x02;
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
internal static extern bool DeleteObject(IntPtr hObject);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
internal static extern int InvalidateRect(IntPtr hwnd, IntPtr rect, int bErase);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
internal static extern IntPtr GetDC(IntPtr hwnd);
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
internal static extern IntPtr CreateCompatibleDC(IntPtr hdc);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
internal static extern int ReleaseDC(IntPtr hwnd, IntPtr hdc);
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
internal static extern int DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
internal static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj);
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
internal static extern IntPtr CreateDIBSection(IntPtr hdc, ref BITMAPINFO bmi, uint iUsage,
out IntPtr bits, IntPtr hSection, uint dwOffset);
[DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
internal static extern void CopyMemory(IntPtr dest, IntPtr src, uint count);
[StructLayout(LayoutKind.Sequential)]
internal struct BITMAPINFO
{
public Int32 biSize;
public Int32 biWidth;
public Int32 biHeight;
public Int16 biPlanes;
public Int16 biBitCount;
public Int32 biCompression;
public Int32 biSizeImage;
public Int32 biXPelsPerMeter;
public Int32 biYPelsPerMeter;
public Int32 biClrUsed;
public Int32 biClrImportant;
}
}
#endregion
public static Image VisualStyleRendererToImage(VisualStyleElement element, Rectangle bounds)
{
if (ToolStripManager.VisualStylesEnabled && VisualStyleRenderer.IsElementDefined(element))
{
VisualStyleRenderer renderer = new VisualStyleRenderer(element);
using (Bitmap bit = new Bitmap(bounds.Width, bounds.Height, PixelFormat.Format32bppArgb))
{
NativeMethods.BITMAPINFO bmi = new NativeMethods.BITMAPINFO();
bmi.biWidth = bit.Width;
bmi.biHeight = bit.Height;
bmi.biPlanes = 1;
bmi.biBitCount = 32;
bmi.biXPelsPerMeter = (int)bit.HorizontalResolution;
bmi.biYPelsPerMeter = (int)bit.VerticalResolution;
bmi.biSize = Marshal.SizeOf(typeof(NativeMethods.BITMAPINFO));
IntPtr bits;
IntPtr bmp = NativeMethods.CreateDIBSection(IntPtr.Zero, ref bmi,
NativeMethods.DIB_RGB_COLORS, out bits, IntPtr.Zero, 0);
IntPtr dc = NativeMethods.GetDC(IntPtr.Zero);
IntPtr hdc = NativeMethods.CreateCompatibleDC(dc);
NativeMethods.SelectObject(hdc, bmp);
using (Graphics g = Graphics.FromHdc(hdc))
{
renderer.DrawBackground(g, bounds);
}
Bitmap image = new Bitmap(bounds.Width, bounds.Height, PixelFormat.Format32bppPArgb);
using (Bitmap tempImage = new Bitmap(bounds.Width, bounds.Height, bounds.Width * 4,
PixelFormat.Format32bppPArgb, bits))
{
BitmapData tempBitmapData = tempImage.LockBits(bounds, ImageLockMode.ReadOnly,
PixelFormat.Format32bppPArgb);
BitmapData bitmapData = image.LockBits(bounds, ImageLockMode.WriteOnly,
PixelFormat.Format32bppPArgb);
NativeMethods.CopyMemory(bitmapData.Scan0, tempBitmapData.Scan0,
(uint)tempBitmapData.Stride * (uint)tempBitmapData.Height);
tempImage.UnlockBits(tempBitmapData);
image.UnlockBits(bitmapData);
}
NativeMethods.DeleteObject(bmp);
NativeMethods.DeleteDC(hdc);
NativeMethods.ReleaseDC(IntPtr.Zero, dc);
return image;
}
}
else
{
return new Bitmap(bounds.Width, bounds.Height);
}
}
}
Reference:
URL1: https://www.autoitscript.com/forum/topic/181956-drawthemebackground-bitmap-alpha/
URL2: https://gist.github.com/wavescholar/11297223#file-gdi-bitmap-conversion-L71
URL3: https://www.experts-exchange.com/questions/20872978/BITMAPINFOHEADER-from-NET-Bitmap.html

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