我从BitmapSource (RenderTargetBitmap)中提取了位图,其中包含蓝色圆圈。 RenderTargetBitmap是使用PixelFormats.Pbgra32创建的。
PixelFormats Pbgra32
将每个颜色通道预先乘以alpha值。因此,当我尝试将位图转换为光标时,我的图像变得不那么透明。
我找到了问题here的解决方案,它将位图克隆到Format24bppRgb
并手动设置R,B,G和alpha值。但是,解决方案完全正常,但对于克隆的位图,我看到了视觉上的黑色边框。
我可以摆脱克隆位图中的黑色边框吗? (我怀疑它是SafeCopy方法中的内容)
从链接中使用的方法是:
private static void SafeCopy(BitmapData srcData, BitmapData dstData, byte alphaLevel)
{
for (int y = 0; y < srcData.Height; y++)
for (int x = 0; x < srcData.Width; x++)
{
byte b = Marshal.ReadByte(srcData.Scan0, y * srcData.Stride + x * 3);
byte g = Marshal.ReadByte(srcData.Scan0, y * srcData.Stride + x * 3 + 1);
byte r = Marshal.ReadByte(srcData.Scan0, y * srcData.Stride + x * 3 + 2);
Marshal.WriteByte(dstData.Scan0, y * dstData.Stride + x * 4, b);
Marshal.WriteByte(dstData.Scan0, y * dstData.Stride + x * 4 + 1, g);
Marshal.WriteByte(dstData.Scan0, y * dstData.Stride + x * 4 + 2, r);
Marshal.WriteByte(dstData.Scan0, y * dstData.Stride + x * 4 + 3, alphaLevel);
}
}
private static Cursor CreateCustomCursorInternal(Bitmap bitmap, double opacity)
{
Bitmap cursorBitmap = null;
IconInfo iconInfo = new IconInfo();
Rectangle rectangle = new Rectangle(0, 0, bitmap.Width, bitmap.Height);
try
{
byte alphaLevel = System.Convert.ToByte(byte.MaxValue * opacity);
// Here, the pre-multiplied alpha channel is specified
cursorBitmap = new Bitmap(bitmap.Width, bitmap.Height,
PixelFormat.Format32bppPArgb);
// Assuming the source bitmap can be locked in a 24 bits per pixel format
BitmapData bitmapData = bitmap.LockBits(rectangle, ImageLockMode.ReadOnly,
PixelFormat.Format24bppRgb);
BitmapData cursorBitmapData = cursorBitmap.LockBits(rectangle,
ImageLockMode.WriteOnly, cursorBitmap.PixelFormat);
// Use SafeCopy() to set the bitmap contents
SafeCopy(bitmapData, cursorBitmapData, alphaLevel);
cursorBitmap.UnlockBits(cursorBitmapData);
bitmap.UnlockBits(bitmapData);
.......
}
原始位图:
克隆位图:
答案 0 :(得分:2)
将WPF 32位PBGRA位图转换为WinForms PARGB位图并同时应用全局不透明度的最简单方法似乎是将所有A,R,G和B值与不透明度因子(浮点值之间)相乘0和1)类似于下面显示的方法。但是,我原本预计也需要交换字节,但显然它不是。
private static void CopyBufferWithOpacity(byte[] sourceBuffer,
System.Drawing.Imaging.BitmapData targetBuffer, double opacity)
{
for (int i = 0; i < sourceBuffer.Length; i++)
{
sourceBuffer[i] = (byte)Math.Round(opacity * sourceBuffer[i]);
}
Marshal.Copy(sourceBuffer, 0, targetBuffer.Scan0, sourceBuffer.Length);
}
给定32位PBGRA位图pbgraBitmap
(例如RenderTargetBitmap),您将使用如下方法:
var width = pbgraBitmap.PixelWidth;
var height = pbgraBitmap.PixelHeight;
var stride = width * 4;
var buffer = new byte[stride * height];
pbgraBitmap.CopyPixels(buffer, stride, 0);
var targetFormat = System.Drawing.Imaging.PixelFormat.Format32bppPArgb;
var bitmap = new System.Drawing.Bitmap(width, height, targetFormat);
var bitmapData = bitmap.LockBits(
new System.Drawing.Rectangle(0, 0, width, height),
System.Drawing.Imaging.ImageLockMode.WriteOnly,
targetFormat);
CopyBufferWithOpacity(buffer, bitmapData, 0.6);
bitmap.UnlockBits(bitmapData);