奇怪的CGImage创建问题
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从iPhone上的原始数据创建CGImageRef时遇到一个非常奇怪的问题。我正在尝试从Perlin噪声生成函数创建CGImageRef，该函数接受x，y，z和t并返回介于-1和1之间的值。对于每个像素，我得到的噪声值介于-1和1之间，将此转换为0到255之间的char，并以以下方式从数据中创建CGImageRef ...
int width = (int)frame.size.width;
int height = (int)frame.size.height;
char* rgba = (char*)malloc(width * height * 4);
//set pixel data
int i = 0;
for(float x = 0.0; x < width; x+=1.0) {
for (float y = 0.0; y < height; y+=1.0) {
float perlinF = ABS([perlinGenerator perlinNoiseX:x y:y z:0.0 t:0.0]);
char perlin = (char)( perlinF * 255.0 );
rgba[4*i] = perlin;
rgba[4*i+1] = perlin;
rgba[4*i+2] = perlin;
rgba[4*i+3] = 255;
i++;
}
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef bitmapContext = CGBitmapContextCreate(
rgba,
width,
height,
8, // bitsPerComponent
4*width, // bytesPerRow
colorSpace,
kCGImageAlphaNoneSkipLast);
CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
for (CGFloat x = 0.0; x<size.width; x+=1.0) {
for (CGFloat y=0.0; y< size.height; y+=1.0) {
float perlinF = ABS([perlinGenerator perlinNoiseX:x y:y z:0.0 t:0.0]);
char perlin = (char)( perlinF * 255.0 );
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, (float)perlin / 255.0);
CGContextFillRect(context, CGRectMake(x, y, 1.0, 1.0));
}
}
没有找到相关结果
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宠封钞轰
int i = 0; for (float y = 0.0; y < height; y+=1.0) { for(float x = 0.0; x < width; x+=1.0) { float perlinF = ABS([perlinGenerator perlinNoiseX:x y:y z:0.0 t:0.0]); char perlin = (char)( perlinF * 255.0 ); rgba[4*i] = perlin; rgba[4*i+1] = perlin; rgba[4*i+2] = perlin; rgba[4*i+3] = 255; i++; } }