I'm trying to place an image that has no definitive shape (a hat for example) on top of a different image control.
The thing is, since the control has a definitive shape, it leaves the default background color to cover up the space left blank. The image control is the exact same size of the image.
I tried using control.BackColor = Color.Transparent; but it doesn't seem to work.
Any other suggestions?
You can use Control.Region for this purpose
GraphicsPath path = new GraphicsPath();
path.AddEllipse(control.ClientRectangle);
control.Region = new Region(path);
try this, you can create any shape using GraphicsPath and set it to Region for instance I created ellipse.
Edit
If you just want to set BackColor = Color.Transparent. for some reason some controls doesn't allow this. in such cases you can do the following
public class CustomControl1 : Control
{
public CustomControl1()
{
this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
}
}
Create a descendant of your control and set this.SetStyle(ControlStyles.SupportsTransparentBackColor, true); that should do the trick
If your Image Control (like a PictureBox) is not moved (by holding mouse down and dragging) by user at runtime, you can use this technique which allows you to display images on top of each other. The images should have transparent background:
public class ImageControl : Control {
public ImageControl(){
SetStyle(ControlStyles.Opaque, true);
}
public Image Image {get;set;}
protected override CreateParams CreateParams {
get {
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20;
return cp;
}
}
protected override void OnPaint(PaintEventArgs e){
if(Image != null) e.Graphics.DrawImage(Image, Point.Empty);
}
}
You can use the control above instead of a PictureBox. Moving this control by dragging at runtime causes flicker much. So if you want so I think there is only 1 solution which uses Region. In this approach, you have to turn your Bitmap to a Region and assign this Region for your Control.Region property. The link given by Chris Dunaway is very helpful for you to do this. However I have to say that the Region has not a smooth border as you may expect. That's a shortage of this approach. For your convenience, I'll post the code with a little modification here, this code uses LockBits which will outperform the original code:
public class Util {
//invert will toggle backColor to foreColor (in fact, I mean foreColor here is the Solid Color which makes your image distinct from the background).
public static Region RegionFromBitmap(Bitmap bm, Color backColor, bool invert)
{
Region rgn = new Region();
rgn.MakeEmpty();//This is very important
int argbBack = backColor.ToArgb();
BitmapData data = bm.LockBits(new Rectangle(0, 0, bm.Width, bm.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
int[] bits = new int[bm.Width * bm.Height];
Marshal.Copy(data.Scan0, bits, 0, bits.Length);
//
Rectangle line = Rectangle.Empty;
line.Height = 1;
bool inImage = false;
for (int i = 0; i < bm.Height; i++)
{
for (int j = 0; j < bm.Width; j++)
{
int c = bits[j + i * bm.Width];
if (!inImage)
{
if (invert ? c == argbBack : c != argbBack)
{
inImage = true;
line.X = j;
line.Y = i;
}
}
else if(invert ? c != argbBack : c == argbBack)
{
inImage = false;
line.Width = j - line.X;
rgn.Union(line);
}
}
}
bm.UnlockBits(data);
return rgn;
}
}
//Use the code
//if your Bitmap is a PNG with transparent background, you can get the Region from it like this:
Region rgn = Util.RegionFromBitmap(yourPng, Color.FromArgb(0), false);
//if your Bitmap has a figure with solid color of Black, you can get the Region like this:
Region rgn = Util.RegionFromBitmap(yourPng, Color.Black, true);
Related
I am using SourceGrid (https://www.nuget.org/packages/SourceGrid) in my WinForms app and I want to custom draw a cell. I have found a way to do it, I just feel there must be a better, less hacky way. Here is what I do:
When creating a new cell:
Cell c = new Cell(Value);
var v = new SourceGrid.Cells.Views.Cell();
v.ElementText = new MyCustomCellElement(); // this will draw for me
c.View = v;
Later when filling the cells with data:
((Grid[row][col].View as SourceGrid.Cells.Views.Cell).ElementText as MyCustomCellElement).MyCustomData = MyCustomObj;
And the code that does the custom draw:
class MyCustomCellElement : DevAge.Drawing.VisualElements.TextGDI
{
public MyObject MyCustomData { get; set; }
protected override void OnDraw(GraphicsCache graphics, RectangleF area)
{
if (Value == null || Value.Length == 0)
return;
SolidBrush brush;
if (Enabled)
brush = graphics.BrushsCache.GetBrush(ForeColor);
else
brush = graphics.BrushsCache.GetBrush(Color.FromKnownColor(KnownColor.GrayText));
// do your draw here, this is the default:
graphics.Graphics.DrawString(Value, Font, brush, area, StringFormat);
}
}
The double cast when putting data in the cell doesn't smell right - it is a hack. It works but I am sure there is a 'proper' way to do it.
I am having some trouble with a custom circular progress bar control. I am trying to overlap the two of them at the lower right corner. It has a transparent background, which obviously in WinForms is showing the background, but has no effect on each other.
Here is what I am seeing:
I have been researching on stackoverflow, and have found a few answers to people having this issue with custom picturebox controls. Most of the solutions, seem to have no effect on the circular progress bar control. Some of the solutions I have tried is.
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20;
return cp;
}
}
I also have the code on the custom control for allowing transparent backgrounds. Obviously, as I stated, this does not effect overlapping controls.
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
There is also a TransparentControl solution on stackoverflow which I saw people using. I have created the control, but either have no idea how to use it, or it doesn't work in my situation. Here is the code from that control.
public class TransparentControl : Panel
{
public bool drag = false;
public bool enab = false;
private int m_opacity = 100;
private int alpha;
public TransparentControl()
{
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
SetStyle(ControlStyles.Opaque, true);
this.BackColor = Color.Transparent;
}
public int Opacity
{
get
{
if (m_opacity > 100)
{
m_opacity = 100;
}
else if (m_opacity < 1)
{
m_opacity = 1;
}
return this.m_opacity;
}
set
{
this.m_opacity = value;
if (this.Parent != null)
{
Parent.Invalidate(this.Bounds, true);
}
}
}
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle = cp.ExStyle | 0x20;
return cp;
}
}
protected override void OnPaint(PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle bounds = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
Color frmColor = this.Parent.BackColor;
Brush bckColor = default(Brush);
alpha = (m_opacity * 255) / 100;
if (drag)
{
Color dragBckColor = default(Color);
if (BackColor != Color.Transparent)
{
int Rb = BackColor.R * alpha / 255 + frmColor.R * (255 - alpha) / 255;
int Gb = BackColor.G * alpha / 255 + frmColor.G * (255 - alpha) / 255;
int Bb = BackColor.B * alpha / 255 + frmColor.B * (255 - alpha) / 255;
dragBckColor = Color.FromArgb(Rb, Gb, Bb);
}
else
{
dragBckColor = frmColor;
}
alpha = 255;
bckColor = new SolidBrush(Color.FromArgb(alpha, dragBckColor));
}
else
{
bckColor = new SolidBrush(Color.FromArgb(alpha, this.BackColor));
}
if (this.BackColor != Color.Transparent | drag)
{
g.FillRectangle(bckColor, bounds);
}
bckColor.Dispose();
g.Dispose();
base.OnPaint(e);
}
protected override void OnBackColorChanged(EventArgs e)
{
if (this.Parent != null)
{
Parent.Invalidate(this.Bounds, true);
}
base.OnBackColorChanged(e);
}
protected override void OnParentBackColorChanged(EventArgs e)
{
this.Invalidate();
base.OnParentBackColorChanged(e);
}
}
Any assistance would be appreciated. This has been driving me nuts for hours. Thanks :)
UPDATE 1: I tried using the following code snippet from examples posted below. This yielded the same results. I still have that blank space between the circular progress bars (as seen in the picture).
Parent.Controls.Cast<Control>()
.Where(c => Parent.Controls.GetChildIndex(c) > Parent.Controls.GetChildIndex(this))
.Where(c => c.Bounds.IntersectsWith(this.Bounds))
.OrderByDescending(c => Parent.Controls.GetChildIndex(c))
.ToList()
.ForEach(c => c.DrawToBitmap(bmp, c.Bounds));
Still stumped. :(
UPDATE 2: I tried setting the front circularprogressbar to use the back circularprogressbar as it's parent in the FormLoad. That didn't work out either. It made them transparent to each other, but cut off any part of the top circularprogressbar that wasn't within' the boundaries of the back.
var pts = this.PointToScreen(circularprogressbar1.Location);
pts = circularprogressbar2.PointToClient(pts);
circularprogressbar1.Parent = circularprogressbar2;
circularprogressbar1.Location = pts;
I'm going to give you just a couple of suggestions on how to proceed.
Start off with this bare-bones transparent control (TransparentPanel).
This class is derived from Panel. That's the first choice to make: is Panel the right control to inherit from/extend for this task? Maybe it is, maybe not.
For example, a Panel is a container. Do you need the features of a container, here? Container means a lot. It inherits ScrollableControl and has ContainerControl among its Window styles. It comes with a baggage already.
You could opt for a Label instead, it's light-weight. Or build a UserControl.
I don't think there's an absolute best choice. It depends of what this custom control is used for. You need to try it out.
Note:
To create the rotation effect with the code shown here, you need the TransparentPanel Control shown below, it won't work the same way drawing on the surface of a standard Control.
This Control generates sort of a persistence in the drawn shapes, which won't exist using another type of Control as canvas (not without tweaking it heavily, that is).
class TransparentPanel : Panel
{
internal const int WS_EX_TRANSPARENT = 0x00000020;
public TransparentPanel() => InitializeComponent();
protected void InitializeComponent()
{
this.SetStyle(ControlStyles.AllPaintingInWmPaint |
ControlStyles.Opaque |
ControlStyles.ResizeRedraw |
ControlStyles.SupportsTransparentBackColor |
ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
}
protected override CreateParams CreateParams
{
get {
var cp = base.CreateParams;
cp.ExStyle |= WS_EX_TRANSPARENT;
return cp;
}
}
}
Other notes:
Here, ControlStyles.SupportsTransparentBackColor is set explicitly. The Panel class already supports this. It's specified anyway because it gives the idea of what this custom control is for just reading at its constructor.
Also, ControlStyles.OptimizedDoubleBuffer is set to false.
This prevents the System to interfere in any way with the painting of the control. There's no caching, the Custom Control is painted new when it's Invalidated. The container Form should preferably have its DoubleBuffer property set to true, but you might want test it without, to see if there's a difference.
This Custom Control (not to be confused with a UserControl) is completely transparent. It doesn't draw its background. But you can paint anything on its surface.
Take the links posted before:
This Translucent Label (no BackGround painting, disabled DoubleDuffering)
Reza Aghaei's transparent Panel (using Opacity in a different way)
TaW's Grid Panel (Color.Transparent and DoubleBuffer)
These notes: Reasons for why a WinForms label does not want to be transparent?
4 different ways to get to the same result. Which one to choose depends on the context/destination.
A design-time advice: when you are testing a custom control functionalities, remember to always rebuild the project. It can happen that a CustomControl, droppen on a Form from the Toolbox, is not updated with the new changes when the project is run.
Also, if you add or remove properties, you need to delete the control, rebuild and drop a new one on the Form.
If you don't, there's a really good chance that your modification/addition are completely ignored and you keep on testing features that never get into play.
An example, using 2 overlapping custom controls.
(using the bare-bones custom TransparentPanel)
This is the test code used to generate these drawings:
Create a new Custom Control using the TransparentPanel class shown before:
Drop two TransparentPanel objects on a test Form
Assign to TransparentPanel1 and TransparentPanel2 the transparentPanel1_Paint and transparentPanel2_Paint event handlers.
Overlap the two transparent Panels, making sure you don't nest them by mistake.
Adapt the rest of the code (you need just a Button, here named btnRotate, assign the btnRotate_Click handler)
private System.Windows.Forms.Timer RotateTimer = null;
private float RotationAngle1 = 90F;
private float RotationAngle2 = 0F;
public bool RotateFigures = false;
public form1()
{
InitializeComponent();
RotateTimer = new Timer();
RotateTimer.Interval = 50;
RotateTimer.Enabled = false;
RotateTimer.Tick += new EventHandler(this.RotateTick);
}
protected void RotateTick(object sender, EventArgs e)
{
RotationAngle1 += 10F;
RotationAngle2 += 10F;
transparentPanel1.Invalidate();
transparentPanel2.Invalidate();
}
private void btnRotate_Click(object sender, EventArgs e)
{
RotateTimer.Enabled = !RotateTimer.Enabled;
if (RotateTimer.Enabled == false)
{
RotateFigures = false;
RotationAngle1 = 90F;
RotationAngle2 = 0F;
}
else
{
RotateFigures = true;
}
}
private void transparentPanel1_Paint(object sender, PaintEventArgs e)
{
if (!RotateFigures) return;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
e.Graphics.CompositingMode = CompositingMode.SourceOver;
Rectangle rect = transparentPanel1.ClientRectangle;
Rectangle rectInner = rect;
using (Pen transpPen = new Pen(transparentPanel1.Parent.BackColor, 10))
using (Pen penOuter = new Pen(Color.SteelBlue, 8))
using (Pen penInner = new Pen(Color.Teal, 8))
using (Matrix m1 = new Matrix())
using (Matrix m2 = new Matrix())
{
m1.RotateAt(-RotationAngle1, new PointF(rect.Width / 2, rect.Height / 2));
m2.RotateAt(RotationAngle1, new PointF(rect.Width / 2, rect.Height / 2));
rect.Inflate(-(int)penOuter.Width, -(int)penOuter.Width);
rectInner.Inflate(-(int)penOuter.Width * 3, -(int)penOuter.Width * 3);
e.Graphics.Transform = m1;
e.Graphics.DrawArc(transpPen, rect, -4, 94);
e.Graphics.DrawArc(penOuter, rect, -90, 90);
e.Graphics.ResetTransform();
e.Graphics.Transform = m2;
e.Graphics.DrawArc(transpPen, rectInner, 190, 100);
e.Graphics.DrawArc(penInner, rectInner, 180, 90);
}
}
private void transparentPanel2_Paint(object sender, PaintEventArgs e)
{
if (!RotateFigures) return;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
e.Graphics.CompositingMode = CompositingMode.SourceOver;
Rectangle rect = transparentPanel2.ClientRectangle;
Rectangle rectInner = rect;
using (Pen transpPen = new Pen(transparentPanel2.Parent.BackColor, 10))
using (Pen penOuter = new Pen(Color.Orange, 8))
using (Pen penInner = new Pen(Color.DarkRed, 8))
using (Matrix m1 = new Matrix())
using (Matrix m2 = new Matrix())
{
m1.RotateAt(RotationAngle2, new PointF(rect.Width / 2, rect.Height / 2));
m2.RotateAt(-RotationAngle2, new PointF(rect.Width / 2, rect.Height / 2));
rect.Inflate(-(int)penOuter.Width, -(int)penOuter.Width);
rectInner.Inflate(-(int)penOuter.Width * 3, -(int)penOuter.Width * 3);
e.Graphics.Transform = m1;
e.Graphics.DrawArc(transpPen, rect, -4, 94);
e.Graphics.DrawArc(penOuter, rect, 0, 90);
e.Graphics.ResetTransform();
e.Graphics.Transform = m2;
e.Graphics.DrawArc(transpPen, rectInner, 190, 100);
e.Graphics.DrawArc(penInner, rectInner, 180, 90);
}
}
I was wanting to get an image to fill a picture box, but not leaving any whitespace. Thus cutting off parts of the image to fit when its not resized to the aspect ratio of the pictureBox. And to adjust as the user resizes the window/pictureBox. The existing options, Sizemode = Zoom leaves whitespace, as its afraid to cut off any of the image and Sizemode = StretchImage stretches the image, distorting it.
The only way I can think of doing this is creating an algorithm to resize the image, keeping the contrast ratio, and setting the width or length of the image to the pictureBox width or length and creating some runtime loop which runs the algorithm once a frame. It seems kind of performance heavy for what it does and kind of hackish. Is there a better option?
Edit:
For anyone coming by, I implemented Ivan Stoev's solution slightly differently:
class ImageHandling
{
public static Rectangle GetScaledRectangle(Image img, Rectangle thumbRect)
{
Size sourceSize = img.Size;
Size targetSize = thumbRect.Size;
float scale = Math.Max((float) targetSize.Width / sourceSize.Width, (float) targetSize.Height / sourceSize.Height);
var rect = new RectangleF();
rect.Width = scale * sourceSize.Width;
rect.Height = scale * sourceSize.Height;
rect.X = (targetSize.Width - rect.Width) / 2;
rect.Y = (targetSize.Height - rect.Height) / 2;
return Rectangle.Round(rect);
}
public static Image GetResizedImage(Image img, Rectangle rect)
{
Bitmap b = new Bitmap(rect.Width, rect.Height);
Graphics g = Graphics.FromImage((Image) b);
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.DrawImage(img, 0, 0, rect.Width, rect.Height);
g.Dispose();
try
{
return (Image)b.Clone();
}
finally
{
b.Dispose();
b = null;
g = null;
}
}
public Form1()
{
InitializeComponent();
updateMainBackground();
}
void updateMainBackground()
{
Image img = Properties.Resources.BackgroundMain;
Rectangle newRect = ImageHandling.GetScaledRectangle(img, mainBackground.ClientRectangle);
mainBackground.Image = ImageHandling.GetResizedImage(img, newRect);
}
private void Form1_Resize(object sender, EventArgs e)
{
updateMainBackground();
}
}
If I understand correctly, you are seeking for a "Fill" mode (similar to Windows background picture). There is no standard way of doing that, but it's not so hard to make your own with the help of a small calculation and GDI+:
using System;
using System.Drawing;
using System.IO;
using System.Net;
using System.Windows.Forms;
namespace Samples
{
public class ImageFillBox : Control
{
public ImageFillBox()
{
SetStyle(ControlStyles.Selectable | ControlStyles.SupportsTransparentBackColor, false);
SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.Opaque | ControlStyles.UserPaint | ControlStyles.ResizeRedraw, true);
}
private Image image;
public Image Image
{
get { return image; }
set
{
if (image == value) return;
image = value;
Invalidate();
}
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
if (image == null)
e.Graphics.Clear(BackColor);
else
{
Size sourceSize = image.Size, targetSize = ClientSize;
float scale = Math.Max((float)targetSize.Width / sourceSize.Width, (float)targetSize.Height / sourceSize.Height);
var rect = new RectangleF();
rect.Width = scale * sourceSize.Width;
rect.Height = scale * sourceSize.Height;
rect.X = (targetSize.Width - rect.Width) / 2;
rect.Y = (targetSize.Height - rect.Height) / 2;
e.Graphics.DrawImage(image, rect);
}
}
}
static class Test
{
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var testForm = new Form();
testForm.Controls.Add(new ImageFillBox
{
Dock = DockStyle.Fill,
Image = GetImage(#"http://www.celebrityrockstarguitars.com/rock/images/Metall_1.jpg")
});
Application.Run(testForm);
}
static Image GetImage(string path)
{
var uri = new Uri(path);
if (uri.IsFile) return Image.FromFile(path);
using (var client = new WebClient())
return Image.FromStream(new MemoryStream(client.DownloadData(uri)));
}
}
}
According to the PictureBoxSizeMode documentation you can specify PictureBoxSizeMode.Zoom to get the image to keep its aspect ratio. It will zoom as big as possible without any part of the image overflowing the picture box.
And you can play with the Dock property (setting DockStyle.Full) to get the picture box to resize to the size of its container.
There is a fairly simple solution to this. PictureBox.SizeMode has a few settings that will help us out. Zoom will adjust the image to fit in the box and Normal will place the picture with out resizing. What we will want to do is check the height and width of the image and if it is larger than the PictureBox size we will Zoom, if not, we will place it in with Normal. See below:
if (image.Height > pctbx_ImageRecognition.Height || image.Width > pctbx_ImageRecognition.Width)
pctbx_ImageRecognition.SizeMode = PictureBoxSizeMode.Zoom;
else
pctbx_ImageRecognition.SizeMode = PictureBoxSizeMode.Normal;
Is it possible to Draw any Form (without overridding the Paint method) in grayscale.
If I show a Form in a Modal() Dialog, I wan't do show its parent as grayscale.
I noticed this in the Visual Studio Extension Manager. If a progressbar is downloading a package, the underlying window is grayed out.
I am thinking of this:
private void Button1_Click(object sender, EventArgs e)
{
using (var dialog = new Form2())
{
SetGrayscale(this, true);
dialog.ShowDialog();
SetGrayscale(this, false);
}
}
Update
Just setting Form.Enabled = false; is not what I intended. That does not look as good as a grayscale representation of my form.
I think the compiz window decorator for Linux did this with apps that are unresponsive.
As has already been said the way to do this is to overlay another control / form on top of your existing form and have it render a grayscale version of this on top, you could either do this using an additional form placed exactly over the original form, or using something like a Panel positioned on top of all other controls.
Here is a working example of how you might do this when placing another form exactly over the client area of the first. How to use it
using (Grayscale(this))
{
MessageBox.Show("Test");
}
Implementation
public static Form Grayscale(Form tocover)
{
var frm = new Form
{
FormBorderStyle = FormBorderStyle.None,
ControlBox = false,
ShowInTaskbar = false,
StartPosition = FormStartPosition.Manual,
AutoScaleMode = AutoScaleMode.None,
Location = tocover.PointToScreen(tocover.ClientRectangle.Location),
Size = tocover.ClientSize
};
frm.Paint += (sender, args) =>
{
var bmp = GetFormImageWithoutBorders(tocover);
bmp = ConvertToGrayscale(bmp);
args.Graphics.DrawImage(bmp, args.ClipRectangle.Location);
};
frm.Show(tocover);
return frm;
}
private static Bitmap ConvertToGrayscale(Bitmap source)
{
var bm = new Bitmap(source.Width, source.Height);
for (int y = 0; y < bm.Height; y++)
{
for (int x = 0; x < bm.Width; x++)
{
Color c = source.GetPixel(x, y);
var luma = (int)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11);
bm.SetPixel(x, y, Color.FromArgb(luma, luma, luma));
}
}
return bm;
}
private static Bitmap GetControlImage(Control ctl)
{
var bm = new Bitmap(ctl.Width, ctl.Height);
ctl.DrawToBitmap(bm, new Rectangle(0, 0, ctl.Width, ctl.Height));
return bm;
}
private static Bitmap GetFormImageWithoutBorders(Form frm)
{
// Get the form's whole image.
using (Bitmap wholeForm = GetControlImage(frm))
{
// See how far the form's upper left corner is
// from the upper left corner of its client area.
Point origin = frm.PointToScreen(new Point(0, 0));
int dx = origin.X - frm.Left;
int dy = origin.Y - frm.Top;
// Copy the client area into a new Bitmap.
int wid = frm.ClientSize.Width;
int hgt = frm.ClientSize.Height;
var bm = new Bitmap(wid, hgt);
using (Graphics gr = Graphics.FromImage(bm))
{
gr.DrawImage(wholeForm, 0, 0,
new Rectangle(dx, dy, wid, hgt),
GraphicsUnit.Pixel);
}
return bm;
}
}
Note that:
The implementation of Paint is fairly poor - really it should use double buffering so that the grayscale image is pre-rendered to a buffered graphics context so the Paint method just needs to paint the pre-drawn buffer contents. See Custom Drawing Controls in C# – Manual Double Buffering
ConvertToGrayscale is a tad on the slow side, but can probably be sped up
Things will go wrong if someone manages to move the original form for any reason
The image is static, if the base control gets redrawn then ideally the top form should redraw too. I'm not sure how best to detect when a portion of another form has been invalidated.
If I find the time I'll try and fix some of those problems, but the above at least gives you the general idea.
Note that in WPF this would be a lot easier.
Sources:
How to convert a colour image to grayscale
Get the image of a control or form, or a form's client area in C#
I don't think there is a way to do it directly - I think all forms are rendered with sRGB.
A hacky way could be to overlay the form with a copy of it as an image (this is simple to do with Control.DrawToBitMap) and then pass it through a simple GDI matrix to desaturate https://web.archive.org/web/20141230145627/http://bobpowell.net/grayscale.aspx.
Try something like this which would work for most simple controls (you would need to recurse into containers to switch all controls correctly).
private void button1_Click(object sender, EventArgs e)
{
using (var dialog = new Form())
{
Dictionary<Control, Tuple<Color, Color>> oldcolors = new Dictionary<Control, Tuple<Color, Color>>();
foreach (Control ctl in this.Controls)
{
oldcolors.Add(ctl, Tuple.Create(ctl.BackColor, ctl.ForeColor));
// get rough avg intensity of color
int bg = (ctl.BackColor.R + ctl.BackColor.G + ctl.BackColor.B) / 3;
int fg = (ctl.ForeColor.R + ctl.ForeColor.G + ctl.ForeColor.B) / 3;
ctl.BackColor = Color.FromArgb(bg, bg, bg);
ctl.ForeColor = Color.FromArgb(fg, fg, fg);
}
dialog.ShowDialog();
foreach (Control ctl in this.Controls)
{
ctl.BackColor = oldcolors[ctl].Item1;
ctl.ForeColor = oldcolors[ctl].Item2;
}
}
}
There's some really great code for a glass button here: http://www.lukesw.net/articles/GlassButton.aspx
The only trouble I have with this button is that if I apply a gradient to my forms it affects the color of the button so that it's not quite what I chose at design time. I don't know whether it's the code I'm using to apply the form gradient that's causing this or if the button is not totally opaque or what. I tried fooling around with the button code a bit but didn't get anywhere. You can get the code for the button at the link I posted above. Below is the code I'm using for my form gradient which is located in the form itself right now:
private Color _Color1 = Color.Gainsboro;
private Color _Color2 = Color.Blue;
private float _ColorAngle = 60f;
public Color Color1
{
get { return _Color1; }
set {
_Color1 = value;
this.Invalidate(); // Tell the Form to repaint itself
}
}
public Color Color2
{
get { return _Color2; }
set {
_Color2 = value;
this.Invalidate(); // Tell the Form to repaint itself
}
}
public float ColorAngle
{
get { return _ColorAngle; }
set {
_ColorAngle = value;
this.Invalidate(); // Tell the Form to repaint itself
}
}
protected override void OnPaintBackground(PaintEventArgs pevent)
{
Graphics g = pevent.Graphics;
Rectangle rBackground = new Rectangle(0, 0, this.Width, this.Height);
System.Drawing.Drawing2D.LinearGradientBrush bBackground
= new System.Drawing.Drawing2D.LinearGradientBrush(rBackground,
_Color1, _Color2, _ColorAngle);
g.FillRectangle(bBackground, rBackground);
bBackground.Dispose();
}
Any pointers on how I can get this button to display the same at runtime as it does at design time would be greatly appreciated!
In the DrawButtonBackground method in GlowButton.cs, just change the opacity to fully opaque (255):
#region " content "
using (GraphicsPath bb = CreateRoundRectangle(rect, 2))
{
//int opacity = pressed ? 0xcc : 0x7f;
int opacity = 255;
using (Brush br = new SolidBrush(Color.FromArgb(opacity, backColor)))
{
g.FillPath(br, bb);
}
}
#endregion