private void WithTransparentCanvas(Rectangle rect, byte alpha, bool copySource, Action <Win32Canvas> action)
{
if (rect.Width <= 0 || rect.Height <= 0 || alpha == 0)
{
return;
}
IntPtr memoryHdc = Gdi32API.CreateCompatibleDCChecked(hdc);
try
{
IntPtr memoryBitmap = Gdi32API.CreateCompatibleBitmapChecked(hdc, rect.Width, rect.Height);
try
{
var originalBitmap = Gdi32API.SelectObjectChecked(memoryHdc, memoryBitmap);
try
{
if (copySource)
{
Gdi32API.BitBlt(memoryHdc, 0, 0, rect.Width, rect.Height, hdc, rect.X, rect.Y, GDI32RasterOperation.SRCCOPY);
}
using (Win32Canvas memoryCanvas = new Win32Canvas(memoryHdc, offset, objectCache))
{
action(memoryCanvas);
}
Gdi32API.GdiAlphaBlend
(
hdc,
rect.X, rect.Y, rect.Width, rect.Height,
memoryHdc,
0, 0, rect.Width, rect.Height,
BLENDFUNCTION.ConstantAlpha(alpha)
);
}
finally
{
Gdi32API.SelectObjectChecked(memoryHdc, originalBitmap);
}
}
finally
{
Gdi32API.DeleteObject(memoryBitmap);
}
}
finally
{
Gdi32API.DeleteDC(memoryHdc);
}
}
private IntPtr WindowProc(IntPtr hwnd, Win32MessageType uMsg, IntPtr wParam, IntPtr lParam)
{
if (HandleWindowEvent(hwnd, uMsg, wParam, lParam))
{
return(IntPtr.Zero);
}
if (uMsg == Win32MessageType.WM_SETCURSOR)
{
uint lParam32 = (uint)lParam.ToInt64();
var hitTest = (Win32HitTestResult)(lParam32 & 0xFFFF);
if (hitTest == Win32HitTestResult.HTCLIENT)
{
IntPtr cursor = Win32API.LoadImageW(
IntPtr.Zero,
Win32SystemResources.IDC_ARROW,
Win32ImageType.IMAGE_CURSOR,
0, 0,
Win32LoadImageFlags.LR_DEFAULTSIZE | Win32LoadImageFlags.LR_SHARED
);
if (cursor != IntPtr.Zero)
{
Win32API.SetCursor(cursor);
return(IntPtr.Zero);
}
}
}
if (uMsg == Win32MessageType.WM_DESTROY)
{
windows.Remove(hwnd);
Win32API.PostQuitMessage(0);
return(IntPtr.Zero);
}
if (uMsg == Win32MessageType.WM_MOUSEMOVE)
{
if (windows.TryGetValue(hwnd, out var window))
{
uint wParam32 = (uint)wParam.ToInt64();
uint lParam32 = (uint)lParam.ToInt64();
int x = (short)(lParam32 & 0xFFFF);
int y = (short)((lParam32 >> 16) & 0xFFFF);
window.StartupInfo.OnMouseMove(new Point(x, y));
}
return(IntPtr.Zero);
}
if (uMsg == Win32MessageType.WM_CHAR)
{
if (windows.TryGetValue(hwnd, out var window))
{
char c = (char)wParam.ToInt64();
if (!char.IsControl(c))
{
window.StartupInfo.OnTextInput(c.ToString());
}
}
return(IntPtr.Zero);
}
if (uMsg == Win32MessageType.WM_PAINT)
{
PAINTSTRUCT ps = new PAINTSTRUCT();
IntPtr hdc = Win32API.BeginPaint(hwnd, ref ps);
try
{
if (windows.TryGetValue(hwnd, out var window))
{
Rectangle area = new Rectangle(ps.rcPaint.left, ps.rcPaint.top, ps.rcPaint.Width, ps.rcPaint.Height);
using (Win32Bitmap bitmap = Win32Bitmap.Create(hdc, area.Width, area.Height))
{
using (Win32Canvas canvas = graphics.CreateCanvas(bitmap, new Point(-area.X, -area.Y)))
{
window.StartupInfo.OnPaint(canvas, area);
}
bitmap.CopyTo(hdc, area.X, area.Y);
}
}
}
finally
{
Win32API.EndPaint(hwnd, ref ps);
}
return(IntPtr.Zero);
}
if (uMsg == Win32MessageType.WM_SIZE)
{
if (windows.TryGetValue(hwnd, out var window))
{
ulong lParam32 = (uint)lParam.ToInt64();
int width = (short)(lParam32 & 0xFFFF);
int height = (short)((lParam32 >> 16) & 0xFFFF);
window.StartupInfo.OnResize(new Size(width, height));
}
return(IntPtr.Zero);
}
return(Win32API.DefWindowProcW(hwnd, uMsg, wParam, lParam));
}
