gdi+

问题 I asked a question recently, How can I create an Image in GDI+ from a Base64-Encoded string in C++? , which got a response that led me to the answer. Now I need to do the opposite - I have an Image in GDI+ whose image data I need to turn into a Base64-Encoded string. Due to its nature, it's not straightforward. The crux of the issue is that an Image in GDI+ can save out its data to either a file or an IStream*. I don't want to save to a file, so I need to use the resulting stream. Problem is,

问题 I understand it is best practise to call Dispose() on instances of Pen and Brush, except if they've been set to the system-predefined values (eg. System.Drawing.Brushes, System.Drawing.Pens or System.Drawing.SystemBrushes) Trying to dispose a system-defined resource results in an exception being thrown. It doesn't appear to be obvious how you can detect (apart from wrapping the Dispose() call in a try/catch) whether one of these resources is referencing a system-defined or user-defined value.

问题 I am developing a control that is a rectangle area and will draw an ellipse in the rectangle area when a trigger occurs. This control will be able to host other controls like, textbox's, buttons, etc. so the circle will be drawn around them when triggered. I want the circle being drawn as an animation like you were circling the inner controls with a pen. My question is whats the best way to accomplish this. I've been doing some research and I could use WPF animation or I could use GDI+ to

问题 Is it possible to use BitBlt to copy directly out of a GDI+ bitmap without using GetHBitmap? GetHBitmap is slow because it makes a new copy of the whole image, in addition to and slower than the BitBlt copy, and the given HBITMAP must be disposed. The image is large. Is there a way to point BitBlt to use the pixel data of the original GDI+ image? EDIT: I can get a pointer to where the GDI+ bitmap pixel data is in the memory. Can I create an HBITMAP that points to the GDI+ bitmap pixel data to

问题 Is it possible to use BitBlt to copy directly out of a GDI+ bitmap without using GetHBitmap? GetHBitmap is slow because it makes a new copy of the whole image, in addition to and slower than the BitBlt copy, and the given HBITMAP must be disposed. The image is large. Is there a way to point BitBlt to use the pixel data of the original GDI+ image? EDIT: I can get a pointer to where the GDI+ bitmap pixel data is in the memory. Can I create an HBITMAP that points to the GDI+ bitmap pixel data to

问题 I have a custom picturebox control that allows dragging 2 bitmaps separately on the Main image,thus allowing the user to select the location of the 2 bitmaps. For First Bitmap Point src = e.Location; PointF ratio = new PointF((float)src.X / ClientSize.Width, (float)src.Y / ClientSize.Height); LaunchOrigin.textratio = ratio; Point origin = new Point((int)(backupbit1.Width * ratio.X), (int)(backupbit1.Height * ratio.Y)); LaunchOrigin.textorigin = origin; point.X = src.X - origin.X; point.Y =

问题 I am trying to draw a TextBox on the extended glass frame of my form. I won't describe this technique, it's well-known. Here's an example for those who haven't heard of it: http://www.danielmoth.com/Blog/Vista-Glass-In-C.aspx The thing is, it is complex to draw over this glass frame. Since black is considered to be the 0-alpha color, anything black disappears. There are apparently ways of countering this problem: drawing complex GDI+ shapes are not affected by this alpha-ness. For example,

问题 I'm trying to draw a polygon with more than one holes. I tried the following code and it does not work correctly. Please advise. PointF[] mypoly = new PointF[6 + 5 + 5]; mypoly[0] = new PointF(0, 0); mypoly[1] = new PointF(100, 0); mypoly[2] = new PointF(100, 100); mypoly[3] = new PointF(0, 100); mypoly[4] = new PointF(10, 80); mypoly[5] = new PointF(0, 0); mypoly[6] = new PointF(10, 10); mypoly[7] = new PointF(10, 20); mypoly[8] = new PointF(20, 20); mypoly[9] = new PointF(20, 10); mypoly[10

问题 I need to add a dependency on a specific version of GDIPlus. This is the version of GDI+ that i want: I want to be sure that I'm using this version for a specific compatibility reason. I've added an assembly manifest to my executable, defining my dependancy on the version of GdiPlus : <dependency> <dependentAssembly> <assemblyIdentity type="win32" name="Microsoft.Windows.GdiPlus" pubicKeyToken="6595b64144ccf1df" version="5.1.3102.2180" processorArchitecture="x86" language="*" /> <

问题 If i paint a rectangle that is wider than 202 pixels wide with a LinearGradientBrush , i get a color fringe on the left: Given the code for a 202px wide rectangle: private void MainForm_Paint(object sender, PaintEventArgs e) { Rectangle r = new Rectangle(50, 50, 202, 50); Color color1 = Color.FromArgb(unchecked((int)0xFF00024d)); Color color2 = Color.FromArgb(unchecked((int)0xFFd6a20f)); Brush b = new LinearGradientBrush(r, color1, color2, LinearGradientMode.Horizontal); e.Graphics