我之前曾经问过类似的问题。
我想要的是获取Imageview内的图像的RGB像素值，因此它可以是我们想要得到的像素值的任何图像。
这是我用来获取点击图像的点。
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
if ([touch tapCount] == 2) {
//self.imageView.image = nil;
return;
}
CGPoint lastPoint = [touch locationInView:self.imageViewGallery];
NSLog(@"%f",lastPoint.x);
NSLog(@"%f",lastPoint.y);
}
要获取图像，我已粘贴此代码。
+ (NSArray*)getRGBAsFromImage:(UIImage *)image atX:(int)xx andY:(int)yy count:(int)count
{
NSMutableArray *result = [NSMutableArray arrayWithCapacity:count];
/** It requires to get the image into your data buffer, so how can we get the `ImageViewImage` **/
CGImageRef imageRef = [image CGImage];
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char));
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);
// Now your rawData contains the image data in the RGBA8888 pixel format.
int byteIndex = (bytesPerRow * yy) + xx * bytesPerPixel;
for (int ii = 0 ; ii < count ; ++ii)
{
CGFloat red = (rawData[byteIndex] * 1.0) / 255.0;
CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;
CGFloat blue = (rawData[byteIndex + 2] * 1.0) / 255.0;
CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;
byteIndex += 4;
UIColor *acolor = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
[result addObject:acolor];
}
free(rawData);
return result;
}
我是ios的新手，所以请解释一下，并建议一些教程会很棒。
答案 0 :(得分：5)
使用此example article。它正在谈论使用图像的颜色选择器。您可以非常轻松地从中了解所需信息。帮助我在我的应用程序。如果需要任何帮助/建议，请告诉我.. :)
修改
像这样更新您的getPixelColorAtLocation:。它会给你正确的颜色。
- (UIColor*) getPixelColorAtLocation:(CGPoint)point {
UIColor* color = nil;
CGImageRef inImage = self.image.CGImage;
// Create off screen bitmap context to draw the image into. Format ARGB is 4 bytes for each pixel: Alpa, Red, Green, Blue
CGContextRef cgctx = [self createARGBBitmapContextFromImage:inImage];
if (cgctx == NULL) { return nil; /* error */ }
size_t w = CGImageGetWidth(inImage);
size_t h = CGImageGetHeight(inImage);
CGRect rect = {{0,0},{w,h}};
/** Extra Added code for Resized Images ****/
float xscale = w / self.frame.size.width;
float yscale = h / self.frame.size.height;
point.x = point.x * xscale;
point.y = point.y * yscale;
/** ****************************************/
/** Extra Code Added for Resolution ***********/
CGFloat x = 1.0;
if ([self.image respondsToSelector:@selector(scale)]) x = self.image.scale;
/*********************************************/
// Draw the image to the bitmap context. Once we draw, the memory
// allocated for the context for rendering will then contain the
// raw image data in the specified color space.
CGContextDrawImage(cgctx, rect, inImage);
// Now we can get a pointer to the image data associated with the bitmap
// context.
unsigned char* data = CGBitmapContextGetData (cgctx);
if (data != NULL) {
//offset locates the pixel in the data from x,y.
//4 for 4 bytes of data per pixel, w is width of one row of data.
// int offset = 4*((w*round(point.y))+round(point.x));
int offset = 4*((w*round(point.y))+round(point.x))*x; //Replacement for Resolution
int alpha = data[offset];
int red = data[offset+1];
int green = data[offset+2];
int blue = data[offset+3];
NSLog(@"offset: %i colors: RGB A %i %i %i %i",offset,red,green,blue,alpha);
color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];
}
// When finished, release the context
CGContextRelease(cgctx);
// Free image data memory for the context
if (data) { free(data); }
return color;
}
让我知道此修复无效.. :)
我的代码是the GitHub。用它来实现选择器图像。如果需要更多信息，请告诉我
答案 1 :(得分：2)
只需使用此方法，它适用于我：
- (UIColor*) getPixelColorAtLocation:(CGPoint)point
{
UIColor* color = nil;
CGImageRef inImage;
inImage = imgZoneWheel.image.CGImage;
// Create off screen bitmap context to draw the image into. Format ARGB is 4 bytes for each pixel: Alpa, Red, Green, Blue
CGContextRef cgctx = [self createARGBBitmapContextFromImage:inImage];
if (cgctx == NULL) { return nil; /* error */ }
size_t w = CGImageGetWidth(inImage);
size_t h = CGImageGetHeight(inImage);
CGRect rect = {{0,0},{w,h}};
// Draw the image to the bitmap context. Once we draw, the memory
// allocated for the context for rendering will then contain the
// raw image data in the specified color space.
CGContextDrawImage(cgctx, rect, inImage);
// Now we can get a pointer to the image data associated with the bitmap
// context.
unsigned char* data = CGBitmapContextGetData (cgctx);
if (data != NULL) {
//offset locates the pixel in the data from x,y.
//4 for 4 bytes of data per pixel, w is width of one row of data.
int offset = 4*((w*round(point.y))+round(point.x));
alpha = data[offset];
int red = data[offset+1];
int green = data[offset+2];
int blue = data[offset+3];
color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];
}
// When finished, release the context
//CGContextRelease(cgctx);
// Free image data memory for the context
if (data) { free(data); }
return color;
}
就这样使用：
UIColor *color = [self getPixelColorAtLocation:lastPoint];
答案 2 :(得分：0)
如果您试图通过CGBitmapContextGetData从图像中获取颜色并设置，例如，在视图背景中，这将是iPhone 6及更高版本中的不同颜色。在iPhone 5中，一切都会好的。有关此Getting the right colors in your iOS app
的更多信息通过UIImage的这个解决方案为您提供了正确的颜色：
- (UIColor *)getColorFromImage:(UIImage *)image pixelPoint:(CGPoint)pixelPoint {
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(pixelPoint.x, pixelPoint.y, 1.f, 1.f));
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return [UIColor colorWithPatternImage:croppedImage];
}
答案 3 :(得分：-2)
您想知道如何从图像视图中获取图像吗？
UIImageView有一个属性，图像。只需使用该属性。