目标C中UIImage的平均颜色值
发布时间:2020-12-16 03:36:07 所属栏目:百科 来源:网络整理
导读:我需要目标c中的图像的平均颜色值.我想创建一个颜色渐变. 有人有想法吗? 解决方法 这里是一个我还没有测试的实验代码. struct pixel { unsigned char r,g,b,a;};- (UIColor*) getDominantColor:(UIImage*)image{ NSUInteger red = 0; NSUInteger green = 0;
我需要目标c中的图像的平均颜色值.我想创建一个颜色渐变.
有人有想法吗? 解决方法
这里是一个我还没有测试的实验代码.
struct pixel { unsigned char r,g,b,a; }; - (UIColor*) getDominantColor:(UIImage*)image { NSUInteger red = 0; NSUInteger green = 0; NSUInteger blue = 0; // Allocate a buffer big enough to hold all the pixels struct pixel* pixels = (struct pixel*) calloc(1,image.size.width * image.size.height * sizeof(struct pixel)); if (pixels != nil) { CGContextRef context = CGBitmapContextCreate( (void*) pixels,image.size.width,image.size.height,8,image.size.width * 4,CGImageGetColorSpace(image.CGImage),kCGImageAlphaPremultipliedLast ); if (context != NULL) { // Draw the image in the bitmap CGContextDrawImage(context,CGRectMake(0.0f,0.0f,image.size.height),image.CGImage); // Now that we have the image drawn in our own buffer,we can loop over the pixels to // process it. This simple case simply counts all pixels that have a pure red component. // There are probably more efficient and interesting ways to do this. But the important // part is that the pixels buffer can be read directly. NSUInteger numberOfPixels = image.size.width * image.size.height; for (int i=0; i<numberOfPixels; i++) { red += pixels[i].r; green += pixels[i].g; blue += pixels[i].b; } red /= numberOfPixels; green /= numberOfPixels; blue/= numberOfPixels; CGContextRelease(context); } free(pixels); } return [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:1.0f]; } 你可以使用这种方法,例如: -(void)doSomething { UIImage *image = [UIImage imageNamed:@"someImage.png"]; UIColor *dominantColor = [self getDominantColor:image]; } 我希望这将适合你. 也可以在UIImage中实现类别.更好地为对象写一些实用程序的方法:) 编辑:修正了while()中的错误. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |