我正在处理一个iphone应用程序，该应用程序将从图像中选择特定的彩色像素，并将其替换为我从颜色菜单中选择的其他颜色阴影。问题是我已经实现的代码在模拟器上工作正常，但是当我在设备上运行相同的代码时，我得到的是，图像的像素仅被白色替换。我正在粘贴下面的代码，如果有人知道如何实现它，那么这将是很好的帮助
// This is data buffer details of whole image's pixels
CGImageRef imageRef = [image CGImage];
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char *rawData = malloc(height * width * 4);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData, width, height,bitsPerComponent, bytesPerRow, colorSpace,kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
//Second image into buffer
//This is data buffer of the pixel to be replaced that i am selecting from image
CGImageRef imageRefs = [selectedColorImage.image CGImage];
NSUInteger widths = CGImageGetWidth(imageRefs);
NSUInteger heights = CGImageGetHeight(imageRefs);
CGColorSpaceRef colorSpaces = CGColorSpaceCreateDeviceRGB();
unsigned char *rawDatas = malloc(heights * widths * 4);
NSUInteger bytesPerPixels = 4;
NSUInteger bytesPerRows = bytesPerPixels * widths;
NSUInteger bitsPerComponents = 8;
CGContextRef contexts = CGBitmapContextCreate(rawDatas, widths, heights,bitsPerComponents, bytesPerRows, colorSpaces,kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpaces);
CGContextDrawImage(contexts, CGRectMake(0, 0, widths, heights), imageRefs);
CGContextRelease(contexts);
// Now your rawData contains the image data in the RGBA8888 pixel format.
int byteIndex = (bytesPerRow * yy) + xx * bytesPerPixel;
int byteIndexs = (bytesPerRows * 0) + 0 * bytesPerPixels;
int i=0;
for (int ii = 0 ; ii < count ; ++ii)
{
CGFloat redb = (rawData[byteIndex] * 1.0) / 255.0;
CGFloat greenb = (rawData[byteIndex + 1] * 1.0) / 255.0;
CGFloat blueb = (rawData[byteIndex + 2] * 1.0) / 255.0;
CGFloat alphab = (rawData[byteIndex + 3] * 1.0) / 255.0;
CGFloat reds = (rawDatas[byteIndexs] * 1.0) / 255.0;
CGFloat greens = (rawDatas[byteIndexs + 1] * 1.0) / 255.0;
CGFloat blues = (rawDatas[byteIndexs + 2] * 1.0) / 255.0;
CGFloat alphas = (rawDatas[byteIndexs + 3] * 1.0) / 255.0;
/* CGColorRef ref=[[shapeButton backgroundColor] CGColor];
switch(CGColorSpaceGetModel(CGColorGetColorSpace(ref)))
{
case kCGColorSpaceModelMonochrome:
// For grayscale colors, the luminance is the color value
//luminance = components[0];
break;
case kCGColorSpaceModelRGB:
// For RGB colors, we calculate luminance assuming sRGB Primaries as per
// http://en.wikipedia.org/wiki/Luminance_(relative)
//luminance = 0.2126 * components[0] + 0.7152 * components[1] + 0.0722 * components[2];
break;
case kCGColorSpaceModelCMYK:
case kCGColorSpaceModelLab:
case kCGColorSpaceModelDeviceN:
case kCGColorSpaceModelIndexed:
break;
case kCGColorSpaceModelUnknown:
break;
case kCGColorSpaceModelPattern:
break;
//default:
// We don't implement support for non-gray, non-rgb colors at this time.
// Since our only consumer is colorSortByLuminance, we return a larger than normal
// value to ensure that these types of colors are sorted to the end of the list.
//luminance = 2.0;
}
int numComponents = CGColorGetNumberOfComponents(ref);
if (numComponents == 4)
{
const CGFloat *components = CGColorGetComponents(ref);
CGFloat red = components[0];
CGFloat green = components[1];
CGFloat blue = components[2];
CGFloat alpha = components[3];
}*/
if((redb==red/255.0f)&&(greenb=green/255.0f)&&(blueb=blue/255.0f)&&(alphab==alpha/255.0f))
{
if(button_tag ==1)
{
NSLog(@"color matching %d",i);//done
i++;
rawData[byteIndex]=(reds*255.0)/1.0+999999999;
rawData[byteIndex+1]=(blues*255.0)/1.0+000000800.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+999999000.0;
rawData[byteIndex+3]=(alphas*255.0)/255.0;
}
if(button_tag ==2)
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+899989989;
rawData[byteIndex+1]=(blues*255.0)/1.0+898998999.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+899989900.0;
rawData[byteIndex+3]=(alphas*255.0)/255.0;
}
if(button_tag ==3)
{
NSLog(@"color matching %d",i);//done
i++;
rawData[byteIndex]=(reds*255.0)/1.0+999999999;
rawData[byteIndex+1]=(blues*255.0)/1.0+990000800.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+999999000.0;
rawData[byteIndex+3]=(alphas*255.0)/10.0;
}
if(button_tag ==4)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+50.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+50.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+50.0;
rawData[byteIndex+3]=(alphas*0.0)/0.0;
}
if(button_tag ==5)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+255000000.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+000000000.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+000000255.0;
rawData[byteIndex+3]=(alphas*255.0)/10.0;
}
if(button_tag ==6)// done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+0.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+1.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+0.0;
rawData[byteIndex+3]=(alphas*255.0)/0.0;
}
if(button_tag ==7)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+255255255.0f;
rawData[byteIndex+1]=(blues*255.0)/1.0+000255255.0f;
rawData[byteIndex+2]=(greens*255.0)/1.0+255255255.0f;
rawData[byteIndex+3]=(alphas*255.0)/255.0;
}
if(button_tag ==8)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+200.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+200.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+200.0;
rawData[byteIndex+3]=(alphas*0.0)/0.0;
}
if(button_tag ==9)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+1.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+0.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+0.0;
rawData[byteIndex+3]=(alphas*255.0)/0.0;
}
if(button_tag ==10)//done
{
i++;
rawData[byteIndex]=(reds*255.0)/1.0+999999999;
rawData[byteIndex+1]=(blues*255.0)/1.0+990000888.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+999999000.0;
rawData[byteIndex+3]=(alphas*255.0)/10.0;
}
if(button_tag ==11)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+900000000;
rawData[byteIndex+1]=(blues*255.0)/1.0+990000800.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+999999000.0;
rawData[byteIndex+3]=(alphas*255.0)/255.0;
}
if(button_tag ==12)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+150.0f;
rawData[byteIndex+1]=(blues*255.0)/1.0+150.0f;
rawData[byteIndex+2]=(greens*255.0)/1.0+150.0f;
rawData[byteIndex+3]=(alphas*255.0)/255.0f;
}
if(button_tag ==13)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+0.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+0.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+0.0;
rawData[byteIndex+3]=(alphas*255.0)/0.0;
}
if(button_tag ==14)//done
{
NSLog(@"color matching %d",i);
i++;
rawData[byteIndex]=(reds*255.0)/1.0+10.0;
rawData[byteIndex+1]=(blues*255.0)/1.0+10.0;
rawData[byteIndex+2]=(greens*255.0)/1.0+10.0;
rawData[byteIndex+3]=(alphas*255.0)/1.0;
}
}
byteIndex += 4;
//byteIndexs += 4;
}
CGSize size=CGSizeMake(320, 330);
UIImage *newImage= [self imageWithBits:rawData withSize:size];
[backgroundImage setImage:newImage];
[self HideLoadingIndicator];
//free(rawData);
//free(rawDatas);
提前致谢：）
答案 0 :(得分：0)
比较浮点数总是不准确。改为使用原始整数值;它们更容易使用并且更快。
编辑：与此类似的东西应该可以用透明替换白色：
uint32_t *pixels = (pointer to image data);
uint32_t sourceColor = 0xffffffff;
uint32_t destColor = 0x00000000;
size_t pixelCount = width * height;
for (int i = 0; i < pixelCount; i++)
if (pixels[i] == sourceColor)
pixels[i] = destColor;
答案 1 :(得分：0)
虽然我无法确切地告诉你你的问题是什么，但我注意到很多类似的代码：
rawData[byteIndex]=(reds*255.0)/1.0+999999999;
当写入单个字节时，将最大值（255）。在RGBA8像素上执行四次将使其呈现白色和不透明。