我想将位图图像转换为灰度图像。为此,我正在使用 NDK 来提升应用程序性能。我已成功应用其他效果。
问题::
我用来应用灰度的代码取自 C##。所以,我想将它转换成 NDK。我无法完成那部分..
作为引用,我正在放置我如何将青色效果应用于图像的代码。
下面粘贴的代码工作正常。
void applyCyano(Bitmap* bitmap) {
//Cache to local variables
unsigned char* red = (*bitmap).red;
unsigned char* green = (*bitmap).green;
unsigned char* blue = (*bitmap).blue;
unsigned int length = (*bitmap).width * (*bitmap).height;
register unsigned int i;
register unsigned char grey, r, g, b;
for (i = length; i--;) {
grey = ((red[i] * 0.222f) + (green[i] * 0.222f) + (blue[i] * 0.222f));
r = componentCeiling(61.0f + grey);
g = componentCeiling(87.0f + grey);
b = componentCeiling(136.0f + grey);
grey = blackAndWhite(red[i], green[i], blue[i]);
red[i] = overlayPixelComponents(grey, r, 0.9f);
green[i] = overlayPixelComponents(grey, g, 0.9f);
blue[i] = overlayPixelComponents(grey, b, 0.9f);
}
}
应用灰度效果的代码(取自网上的C##例子)::
void applyGrayscaleNatively(Bitmap* original)
{
//create an empty bitmap the same size as original
Bitmap newBitmap = new Bitmap(original.Width, original.Height);
//lock the original bitmap in memory
BitmapData originalData = original.LockBits(
new Rectangle(0, 0, original.Width, original.Height),
ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
//lock the new bitmap in memory
BitmapData newData = newBitmap.LockBits(
new Rectangle(0, 0, original.Width, original.Height),
ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
//set the number of bytes per pixel
int pixelSize = 3;
for (int y = 0; y < original.Height; y++)
{
//get the data from the original image
byte* oRow = (byte*)originalData.Scan0 + (y * originalData.Stride);
//get the data from the new image
byte* nRow = (byte*)newData.Scan0 + (y * newData.Stride);
for (int x = 0; x < original.Width; x++)
{
//create the grayscale version
byte grayScale =
(byte)((oRow[x * pixelSize] * .11) + //B
(oRow[x * pixelSize + 1] * .59) + //G
(oRow[x * pixelSize + 2] * .3)); //R
//set the new image's pixel to the grayscale version
nRow[x * pixelSize] = grayScale; //B
nRow[x * pixelSize + 1] = grayScale; //G
nRow[x * pixelSize + 2] = grayScale; //R
}
}
//unlock the bitmaps
newBitmap.UnlockBits(newData);
original.UnlockBits(originalData);
}
我想做什么::
我从 here 中获取了这个项目为图像设置了不同的效果,但没有为灰度设置。那么如何将灰度应用于代码,以便项目的所有其他功能不会停止。
如果您需要我的帮助,请告诉我。
提前致谢..
请帮助我解决这个问题,因为我无法在我的项目中取得进一步进展。
最佳答案
使用以下函数将位图转换为 Android 中的等效灰度图,而不是转换 C# 版本
public Bitmap toGrayscale(Bitmap bmpOriginal){
int width, height;
height = bmpOriginal.getHeight();
width = bmpOriginal.getWidth();
Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
Canvas c = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
c.drawBitmap(bmpOriginal, 0, 0, paint);
return bmpGrayscale;
}
关于android - 如何对位图图像应用灰度效果?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23053933/