private void Side_pictureBox_Paint(object sender, PaintEventArgs e)
{
if (doubleclicked == true)
{
Side_pictureBox.Refresh();
for (int numbering_for_digram = 1; numbering_for_digram <= No_of_circle; numbering_for_digram++)
{
//MessageBox.Show(numbering_for_digram.ToString());
String drawString = numbering_for_digram.ToString();
// Create font and brush.
Font drawFont = new Font("Calibri (Body)", 20);
SolidBrush drawBrush = new SolidBrush(Color.Blue);
// Create point for upper-left corner of drawing.
//float x = 0;
//float y = 0;
doubleclicked = false;
// Draw string to screen.
e.Graphics.DrawString(drawString, drawFont, drawBrush, lastPoint);
Side_pictureBox.Update();
//MessageBox.Show("passed graphics draw");
}
}
}
}
private void Side_pictureBox_MouseMove(object sender, MouseEventArgs e)
{
if (isMouseDown == true && Edit_Variables.add_remark_now==false)//check to see if the mouse button is down
{
if (lastPoint != null)//if our last point is not null, which in this case we have assigned above
{
if (Side_pictureBox.Image == null)//if no available bitmap exists on the picturebox to draw on
{
//create a new bitmap
Bitmap bmp = new Bitmap(Side_pictureBox.Width, Side_pictureBox.Height);
Side_pictureBox.Image = bmp; //assign the picturebox.Image property to the bitmap created
}
using (Graphics g = Graphics.FromImage(Side_pictureBox.Image))
{//we need to create a Graphics object to draw on the picture box, its our main tool
//when making a Pen object, you can just give it color only or give it color and pen size
g.DrawLine(new Pen(Color.DarkRed, 2), lastPoint, e.Location);
g.SmoothingMode = SmoothingMode.AntiAlias;
//this is to give the drawing a more smoother, less sharper look
}
Side_pictureBox.Invalidate();//refreshes the picturebox
lastPoint = e.Location;//keep assigning the lastPoint to the current mouse position
}
}
This is how the whole process works, firstly I will draw using a "Pen" on an image. This drawing process starts with mousedown and ends with mouseup event. Once mouseup is detected, I am to required to click on a point within the image and it suppose to drawstring(draws "1" on the image) on the image itself. For the first drawstring event it turns out fine. However, once I trigger the mousedown event, it will remove the previous drawstring("1"). Can someone help how can i prevent the "previous" drawstring to be remove? Thank you all alot!
Don't draw directly in the paint box. Draw in the Image of the PaintBox instead. And do this at the end of the your MouseMove event, before calling Side_pictureBox.Invalidate();
Related
I am trying to draw circles using Bitmap.
Each time I click the mouse, the circle I previously drew is moved to the new position.
What I want to happen is: Each time I click the mouse, a new circle is created/drawn at the position I clicked and all previously drawn circles remain without moving.
I am working with the following code:
using System;
using System.Drawing;
using System.Windows.Forms;
namespace multirectangle
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
}
Bitmap background;
Graphics scG;
Rectangle rectangleObj;
private Point clickCurrent = Point.Empty;
private Point clickPrev = Point.Empty;
private void Form1_Load(object sender, EventArgs e)
{
background = new Bitmap(Width, Height);
rectangleObj = new Rectangle(10, 10, 30, 30);
scG = Graphics.FromImage(background);
}
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
clickCurrent = PointToClient(Cursor.Position);
clickPrev = clickCurrent;
if (clickPrev == Point.Empty) return;
rectangleObj.X = clickPrev.X - rectangleObj.Height / 2;// +radius;
rectangleObj.Y = clickPrev.Y - rectangleObj.Width / 2;
Refresh();
}
protected override void OnPaint(PaintEventArgs pe)
{
pe.Graphics.DrawImage(Draw(), 0, 0);
}
public Bitmap Draw()
{
Graphics scG = Graphics.FromImage(background);
Pen myPen = new Pen(System.Drawing.Color.Red, 3);
scG.Clear(SystemColors.Control);
scG.DrawEllipse(myPen, rectangleObj);
return background;
}
}
}
Your English was a little confusing. If I'm understanding your problem correctly, right now the only thing that's being drawn is the new circle where the click was, and you want all the old ones to persist as well? In which case, there are two options:
Don't clear the bitmap before you draw. scG.Clear(SystemColors.Control); will clear the bitmap you just drew. If you remove that line and don't clear the bitmap, then the next time you click, it will then draw the new ellipse right on top of the last bitmap.
If you want a fresh drawing/bitmap everytime, you would need a list of your rectangleObj . Each time you click, you add that point to your rectangleObj collection. Then in your draw method, you would iterate through the collection and draw all of them.
I notice a few things. First, in Form1_MouseDown(), you have this:
clickCurrent = PointToClient(Cursor.Position);
clickPrev = clickCurrent;
You are overwriting the old position (clickPrev) before you even save it. If you want to keep both positions, you should put them in a simple structure, like a List. When you get a new point, just Add() it to the list. Then, in your Draw() routine, loop over all the elements in the list and draw them all.
If you just want two positions--and only two--just swap your statements like this:
clickPrev = clickCurrent;
clickCurrent = PointToClient(Cursor.Position);
And you'll have to allocate another rectangle object for the drawing, although it would make more sense to take care of this in the Draw() routine.
Swap the position of the following statements
clickCurrent = PointToClient(Cursor.Position);
clickPrev = clickCurrent;
I think you are assigning the clickCurrent to clickPrevious after you initialize clickCurrent. It needs to be the other way.
Please try this
Rectangle rectangleObj;
Bitmap background;
Graphics scG;
Pen myPen;
private void Form1_Load(object sender, EventArgs e)
{
rectangleObj = new Rectangle(10, 10, 30, 30);
background = new Bitmap(Width, Height);
scG = Graphics.FromImage(background);
myPen = new Pen(Color.Red, 3);
BackgroundImage = background;
}
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
var point = PointToClient(Cursor.Position);
rectangleObj.X = point.X - rectangleObj.Height / 2;
rectangleObj.Y = point.Y - rectangleObj.Width / 2;
scG.DrawEllipse(myPen, rectangleObj);
Refresh();
}
OnPaint and Draw methods removed. As well as clickCurrent and clickPrev fields.
When you change the form size (for example, maximize it), Bitmap and Graphics remain the same, so you get this effect. To avoid this, you need to add the event handler
private void Form1_SizeChanged(object sender, EventArgs e)
{
background = new Bitmap(Width, Height);
scG = Graphics.FromImage(background);
BackgroundImage = background;
}
Note that each time you resize the form, all previously drawn is erased. If this is undesirable, a different approach is needed for drawing. Let me know, I will give another example.
Let me preface this with a real life product; You may remember in Elementary school, they had scratch paper which basically consisted of a rainbow-colored sheet of paper with a black film on top. You would take a sharp object and peel away the black film to expose the colored paper.
I am attempting to do the same thing using images in a picture box.
My idea consists of these things:
A textured image.
A black rectangle the size of the picture box.
A circle image.
What I am trying to achieve is to open a program, have an image drawn to a picture box with the black rectangle on top of it. Upon clicking the picture box it uses the circle to invert the alpha of the rectangle where I click using the circle as a reference.
My Problem-
I cannot figure out any way to erase (set the transparency of) a part of the black rectangle where I click.
For the life of me, I do not know of any method to cut a window in an image. It is almost like a reverse crop, where I keep the exterior elements rather than the interior, exposing the textured image below.
Can WinForms not do this? Am I crazy? Should I just give up?
I should mention that I prefer not to have to change alpha on a pixel per pixel basis. It would slow the program down far too much to be used as a pseudo-painter. If that is the only way, however, feel free to show.
Here is an image of what I'm trying to achieve:
This is not really hard:
Set the colored image as a PictureBox's BackgroundImage.
Set a black image as its Image.
And draw into the image using the normal mouse events and a transparent Pen..
We need a point list to use DrawCurve:
List<Point> currentLine = new List<Point>();
We need to prepare and clear the the black layer:
private void ClearSheet()
{
if (pictureBox1.Image != null) pictureBox1.Image.Dispose();
Bitmap bmp = new Bitmap(pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
using (Graphics G = Graphics.FromImage(bmp)) G.Clear(Color.Black);
pictureBox1.Image = bmp;
currentLine.Clear();
}
private void cb_clear_Click(object sender, EventArgs e)
{
ClearSheet();
}
To draw into the Image we need to use an associated Graphics object..:
void drawIntoImage()
{
using (Graphics G = Graphics.FromImage(pictureBox1.Image))
{
// we want the tranparency to copy over the black pixels
G.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
G.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
G.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
using (Pen somePen = new Pen(Color.Transparent, penWidth))
{
somePen.MiterLimit = penWidth / 2;
somePen.EndCap = System.Drawing.Drawing2D.LineCap.Round;
somePen.LineJoin = System.Drawing.Drawing2D.LineJoin.Round;
somePen.StartCap = System.Drawing.Drawing2D.LineCap.Round;
if (currentLine.Count > 1)
G.DrawCurve(somePen, currentLine.ToArray());
}
}
// enforce the display:
pictureBox1.Image = pictureBox1.Image;
}
The usual mouse events:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
currentLine.Add(e.Location);
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
currentLine.Add(e.Location);
drawIntoImage();
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
currentLine.Clear();
}
That's all that's needed. Make sure to keep the PB's SizeMode = Normal or else the pixels won't match..!
Note that there are a few challenges when you want to get soft edges, more painting tools, letting a simple click paint a dot or an undo or other finer details to work. But the basics are not hard at all..
Btw, changing Alpha is not any different from changing the color channels.
As an alternative you may want to play with a TextureBrush:
TextureBrush brush = new TextureBrush(pictureBox1.BackgroundImage);
using (Pen somePen = new Pen(brush) )
{
// basically
// the same drawing code..
}
But I found this to be rather slow.
Update:
Using a png-file as a custom tip is a little harder; the main reason is that the drawing is reversed: We don't want to draw the pixels, we want to clear them. GDI+ doesn't support any such composition modes, so we need to do it in code.
To be fast we use two tricks: LockBits will be as fast as it gets and restricting the area to our custom brush tip will prevent wasting time.
Let's assume you have a file to use and load it into a bitmap:
string stampFile = #"yourStampFile.png";
Bitmap stamp = null;
private void Form1_Load(object sender, EventArgs e)
{
stamp = (Bitmap) Bitmap.FromFile(stampFile);
}
Now we need a new function to draw it into our Image; instead of DrawCurve we need to use DrawImage:
void stampIntoImage(Point pt)
{
Point point = new Point(pt.X - stamp.Width / 2, pt.Y - stamp.Height / 2);
using (Bitmap stamped = new Bitmap(stamp.Width, stamp.Height) )
{
using (Graphics G = Graphics.FromImage(stamped))
{
stamp.SetResolution(stamped.HorizontalResolution, stamped.VerticalResolution);
G.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceOver;
G.DrawImage(pictureBox1.Image, 0, 0,
new Rectangle(point, stamped.Size), GraphicsUnit.Pixel);
writeAlpha(stamped, stamp);
}
using (Graphics G = Graphics.FromImage(pictureBox1.Image))
{
G.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
G.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
G.CompositingQuality =
System.Drawing.Drawing2D.CompositingQuality.HighQuality;
G.DrawImage(stamped, point);
}
}
pictureBox1.Image = pictureBox1.Image;
}
A few notes: I found that I hat to do an explicit SetResolution since the stamp file I photoshopped was 72dpi and the default Bitmaps in my program were 120dpi. Watch out for these differences!
I start the Bitmap to be drawn by copying the right part of the current Image.
Then I call a fast routine that applies the alpha of the stamp to it:
void writeAlpha(Bitmap target, Bitmap source)
{
// this method assumes the bitmaps both are 32bpp and have the same size
int Bpp = 4;
var bmpData0 = target.LockBits(
new Rectangle(0, 0, target.Width, target.Height),
ImageLockMode.ReadWrite, target.PixelFormat);
var bmpData1 = source.LockBits(
new Rectangle(0, 0, source.Width, source.Height),
ImageLockMode.ReadOnly, source.PixelFormat);
int len = bmpData0.Height * bmpData0.Stride;
byte[] data0 = new byte[len];
byte[] data1 = new byte[len];
Marshal.Copy(bmpData0.Scan0, data0, 0, len);
Marshal.Copy(bmpData1.Scan0, data1, 0, len);
for (int i = 0; i < len; i += Bpp)
{
int tgtA = data0[i+3]; // opacity
int srcA = 255 - data1[i+3]; // transparency
if (srcA > 0) data0[i + 3] = (byte)(tgtA < srcA ? 0 : tgtA - srcA);
}
Marshal.Copy(data0, 0, bmpData0.Scan0, len);
target.UnlockBits(bmpData0);
source.UnlockBits(bmpData1);
}
I use a simple rule: Reduce target opacity by the source transparency and make sure we don't get negative.. You may want to play around with it.
Now all we need is to adapt the MouseMove; for my tests I have added two RadioButtons to switch between the original round pen and the custom stamp tip:
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
if (rb_pen.Checked)
{
currentLine.Add(e.Location);
drawIntoImage();
}
else if (rb_stamp.Checked) { stampIntoImage(e.Location); };
}
}
I didn't use a fish but you can see the soft edges:
Update 2: Here is a MouseDown that allows for simple clicks:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (rb_pen.Checked) currentLine.Add(e.Location);
else if (rb_stamp.Checked)
{
{ stampIntoImage(e.Location); };
}
}
so am implementing a project that can read image pan it, zoom it and do other stuff.. everything was going well until i tried implementing a draw with right mouse button.
the problem is when i draw a line, the line that appears on the image does not correspond to the line i drew on screen, meaning its shifted and i know its because of the re-sizing and zooming of the image, but when i draw lines on the image with its original size(the image) and with panning also ; i have no problem.
here's the code.
so first here is how i load the image when i click browse and select image
Myimage = new Bitmap(ImagePath);
resized = myImage.Size;
imageResize();
pictureBox.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox_Paint);
pictureBox.Invalidate();
the imageResize function does the following:
void imageResize()
{
//calculated the size to fit the control i will draw the image on
resized.Height = someMath;
resized.Width = someMath;
}
then in the event handler for the pictureBox_Paint event i wrote:
private void pictureBox_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
// Create a local version of the graphics object for the PictureBox.
Graphics PboxGraphics = e.Graphics;
PboxGraphics.DrawImage(myImage, imageULcorner.X, imageULcorner.Y, resized.Width, resized.Height);
}
as you can see the resized size is not the original image size i did this because i wanted the image to show on the picturebox control centralized and filled now the next part IS WHERE MY PROBLEM BEGINS
i have to draw lines on image using right mouse button so i implemented pictureBox_MouseDown & pictureBox_MouseUp event handlers
// mouse down event handler
private void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
else if (mouse.Button == MouseButtons.Right)
{
mouseDown = mouse.Location;
mouseDown.X = mouseDown.X - imageULcorner.X;
mouseDown.Y = mouseDown.Y - imageULcorner.Y;
draw = true;
}
}
here is the mouse up event handler
//Mouse UP
private void pictureBox_MouseUp(object sender, MouseEventArgs e)
{
else if (mouse.Button == MouseButtons.Right)
{
if (draw)
{
mouseLocationNow.X = mouse.X - imageULcorner.X;
mouseLocationNow.Y = mouse.Y - imageULcorner.Y;
//
// get graphics object of the image ( the original not the resized)
// as the resized image only appears when i draw on the graphics of the
// pictureBox control
// i know the problem lies here but how can i fix it
//
Graphics image = Graphics.FromImage(myImage);
Pen pen = new Pen(Color.Red, 2);
image.DrawLine(pen, mouseLocationNow, mouseDown);
pictureBox.Invalidate();
}
draw = false;
}
so in the end i want to be able to draw on the re-sized image and make it correspond to the real image and also to the screen where i draw the line
thanks and sorry for the long post but this problem has been driving me crazy.
Here is a PictureBox subclass that supports the ability to apply zooming not only to the Image but also to graphics you draw onto its surface.
It includes a SetZoom function to zoom in by scaling both itself and a Matrix.
It also has a ScalePoint function you can use to calculate the unscaled coordinates from the pixel coordinates you receive in the mouse events.
The idea is to use a Transformation Matrix to scale any pixels the Graphics object will draw in the Paint event.
I include a little code for the form for testing.
public partial class ScaledPictureBox : PictureBox
{
public Matrix ScaleM { get; set; }
float Zoom { get; set; }
Size ImgSize { get; set; }
public ScaledPictureBox()
{
InitializeComponent();
ScaleM = new Matrix();
SizeMode = PictureBoxSizeMode.Zoom;
}
public void InitImage()
{
if (Image != null)
{
ImgSize = Image.Size;
Size = ImgSize;
SetZoom(100);
}
}
public void SetZoom(float zoomfactor)
{
if (zoomfactor <= 0) throw new Exception("Zoom must be positive");
float oldZoom = Zoom;
Zoom = zoomfactor / 100f;
ScaleM.Reset();
ScaleM.Scale(Zoom , Zoom );
if (ImgSize != Size.Empty) Size = new Size((int)(ImgSize.Width * Zoom),
(int)(ImgSize.Height * Zoom));
}
public PointF ScalePoint(PointF pt)
{ return new PointF(pt.X / Zoom , pt.Y / Zoom ); }
}
Here is the code in the Form that does the testing:
public List<PointF> somePoints = new List<PointF>();
private void scaledPictureBox1_MouseClick(object sender, MouseEventArgs e)
{
somePoints.Add(scaledPictureBox1.ScalePoint(e.Location) );
scaledPictureBox1.Invalidate();
}
private void scaledPictureBox1_Paint(object sender, PaintEventArgs e)
{
// here we apply the scaling matrix to the graphics object:
e.Graphics.MultiplyTransform(scaledPictureBox1.ScaleM);
using (Pen pen = new Pen(Color.Red, 10f))
{
PointF center = new PointF(scaledPictureBox1.Width / 2f,
scaledPictureBox1.Height / 2f);
center = scaledPictureBox1.ScalePoint(center);
foreach (PointF pt in somePoints)
{
DrawPoint(e.Graphics, pt, pen);
e.Graphics.DrawLine(Pens.Yellow, center, pt);
}
}
}
public void DrawPoint(Graphics G, PointF pt, Pen pen)
{
using (SolidBrush brush = new SolidBrush(pen.Color))
{
float pw = pen.Width;
float pr = pw / 2f;
G.FillEllipse(brush, new RectangleF(pt.X - pr, pt.Y - pr, pw, pw));
}
}
Here are the results after drawing a few points showing the same points in four different zoom settings; the ScaledPictureBox is obviously placed in an AutoScroll-Panel. The lines show how to use the regular drawing commands..
I have a pictureBox1 with image inside and when i click on it its drawing points.
Now i added a reset button i called it when i click on it its should clear all the drawings i did on the pictureBox and leavethe image inside without the drawings on it.
I did:
private void button4_Click(object sender, EventArgs e)
{
Graphics graphics;
graphics = pictureBox1.CreateGraphics();
graphics.DrawImage(pictureBox1.Image, 0, 0);
}
So i draw a lot of points on pictureBox1 then click the button and all points are gone but then once i click on the picturebox1 again i see also the new points but also the old points i did before the clearing.
How can i clear the old drawings so it wont show up on the next clicks ?
This is the paint event: Moved the paint event to a new class:
public static void Paint(List<PointF> pb1points, GraphicsPath pb1gp, Point movingPoint, PictureBox pictureBox1, Graphics e)
{
e.Clear(Color.White);
e.DrawImage(pictureBox1.Image, movingPoint);
Pen p;
p = new Pen(Brushes.Green);
foreach (PointF pt in pb1points)
{
e.FillEllipse(Brushes.Red, pt.X, pt.Y, 3f, 3f);
}
using (Pen pp = new Pen(Color.Green, 2f))
{
pp.StartCap = pp.EndCap = LineCap.Round;
pp.LineJoin = LineJoin.Round;
e.DrawPath(pp, pb1gp);
}
}
You can try using Graphics.Clear().
Reference: http://msdn.microsoft.com/en-us/library/system.drawing.graphics.clear(v=vs.110).aspx
setting the Image property to null should work.
picBox.Image = null;
Ii it's not worked ,you might be used the InitialImage property to display your image.
pictBox.InitialImage = null;
Please refer the link:
Clear image on picturebox
This is working:
private void button4_Click(object sender, EventArgs e)
{
Graphics graphics;
graphics = pictureBox1.CreateGraphics();
graphics.DrawImage(pictureBox1.Image, 0, 0);
pb1points = new List<PointF>();
}
I have an image .I want to crop 10 px from left and 10px from right of the image.I used the below code to do so
string oldImagePath="D:\\RD\\dotnet\\Images\\photo1.jpg";
Bitmap myOriginalImage = (Bitmap)Bitmap.FromFile(oldImagePath);
int newWidth = myOriginalImage.Width;
int newHeight = myOriginalImage.Height;
Rectangle cropArea = new Rectangle(10,0, newWidth-10, newHeight);
Bitmap target = new Bitmap(cropArea.Width, cropArea.Height);
using (Graphics g = Graphics.FromImage(target))
{
g.DrawImage(myOriginalImage,cropArea);
}
target.Save("D:\\RD\\dotnet\\Images\\test.jpg");
But this is not giving me the results which i expect. This outputs an image which has 10 px cropped from the right and a resized image.Instead of cropiing it is resizing the width i think.So the image is shrinked(by width). Can any one correct me ? Thanks in advance
Your new width should be reduced by twice the crop margin, since you'll be chopping off that amount from both sides.
Next, when drawing the image into the new one, draw it at a negative offset. This causes the area that you aren't interested in to be clipped off.
int cropX = 10;
Bitmap target = new Bitmap(myOriginalImage.Width - 2*cropX, myOriginalImage.Height);
using (Graphics g = Graphics.FromImage(target))
{
g.DrawImage(myOriginalImage, -cropX, 0);
}
My guess is this line
Rectangle cropArea = new Rectangle(10,0, newWidth-10, newHeight);
should be
Rectangle cropArea = new Rectangle(10,0, newWidth-20, newHeight);
Set the width of the new rectangle to be 20 less than the original - 10 for each side.
Some indication what result it is giving you would be helpful in confirming this.
Corey Ross is correct. Alternately, you can translate along the negative x axis and render at 0.0, 0.0. Should produce identical results.
using (Graphics g = Graphics.FromImage(target))
{
g.TranslateTransform(-cropX, 0.0f);
g.DrawImage(myOriginalImage, 0.0f, 0.0f);
}
You need to use the overload that has you specify both Destination Rectangle, and Source Rectangle.
Below is an interactive form of this using a picture box on a form. It allows you to drag the image around. I suggest making the picture box 100 x 100 and have a much larger image such as a full screen window you've captured with alt-prtscr.
class Form1 : Form
{
// ...
Image i = new Bitmap(#"C:\Users\jasond\Pictures\foo.bmp");
Point lastLocation = Point.Empty;
Size delta = Size.Empty;
Point drawLocation = Point.Empty;
bool dragging = false;
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (!dragging)
{
lastLocation = e.Location;
dragging = true;
}
delta = new Size(lastLocation.X - e.Location.X, lastLocation.Y - e.Location.Y);
lastLocation = e.Location;
if (!delta.IsEmpty)
{
drawLocation.X += delta.Width;
drawLocation.Y += delta.Height;
pictureBox1.Invalidate();
}
}
else
{
dragging = false;
}
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Rectangle source = new Rectangle(drawLocation,pictureBox1.ClientRectangle.Size);
e.Graphics.DrawImage(i,pictureBox1.ClientRectangle,source, GraphicsUnit.Pixel);
}
//...
Okay, I totally fail at explaining this, but hang on:
The DrawImage function requires the location of the image, as well as it's position. You need a second position for cropping as how the old relates to the new, not vice versa.
That was entirely incomprehensible, but here is the code.
g.DrawImage(myOriginalImage, -cropArea.X, -cropArea.Y);
I hope that explains it more then I did.