最近看了下JSQMessage的源码，一个比较优雅的UI库，代码很赞，只用了少量的图片，牵扯了一些UIImage的相关操作。虽然控件比较基本 ，但是一些用法还是不是很清楚，希望接下来能有时间去整理下其他的基础控件。此次仅为UIImage的一些相关操作。
Github下载地址: https://github.com/ChinaFishNews/UIImageDemo
通过颜色生成纯色图片
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| +(UIImage *)imageWithColor:(UIColor *)color
withSize:(CGSize)size{
CGRect rect = CGRectMake(0, 0, size.width, size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
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通过图片生成圆形图片
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| +(UIImage *)circualImage:(UIImage *)image
withDiameter:(NSUInteger)diameter{
CGRect frame = CGRectMake(0.0f, 0.0f, diameter, diameter);
UIImage *newImage = nil;
UIGraphicsBeginImageContextWithOptions(frame.size, NO, [UIScreen mainScreen].scale);
{
UIBezierPath *imgPath = [UIBezierPath bezierPathWithOvalInRect:frame];
[imgPath addClip];
[image drawInRect:frame];
newImage = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();
return newImage;
}
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通过图片或颜色生成圆形图片(如传入颜色则通过颜色生成)
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| +(UIImage *)circualarImage:(UIImage *)image
withDiameter:(NSUInteger)diameter
highlightedColor:(UIColor *)highlightedColor{
CGRect frame = CGRectMake(0.0f, 0.0f, diameter, diameter);
UIImage *newImage = nil;
UIGraphicsBeginImageContextWithOptions(frame.size, NO, [UIScreen mainScreen].scale);
{
CGContextRef context = UIGraphicsGetCurrentContext();
UIBezierPath *imgPath = [UIBezierPath bezierPathWithOvalInRect:frame];
[imgPath addClip];
[image drawInRect:frame];
if (highlightedColor != nil) {
CGContextSetFillColorWithColor(context, highlightedColor.CGColor);
CGContextFillEllipseInRect(context, frame);
}
newImage = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();
return newImage;
}
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在已有图片上添加文字
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| +(UIImage *)addTextInImage:(UIImage *)image
text:(NSString *)text
textColor:(UIColor *)textColor
font:(UIFont *)font{
CGRect frame = CGRectMake(0.0f, 0.0f, image.size.width, image.size.height);
NSDictionary *attributes = @{ NSFontAttributeName : [UIFont systemFontOfSize:33],
NSForegroundColorAttributeName : textColor };
CGRect textFrame = [text boundingRectWithSize:image.size
options:(NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading)
attributes:attributes
context:nil];
CGPoint frameMidPoint = CGPointMake(CGRectGetMidX(frame), CGRectGetMidY(frame));
CGPoint textFrameMidPoint = CGPointMake(CGRectGetMidX(textFrame), CGRectGetMidY(textFrame));
CGFloat dx = frameMidPoint.x - textFrameMidPoint.x;
CGFloat dy = frame.size.height - textFrameMidPoint.y*2;;
CGPoint drawPoint = CGPointMake(dx, dy);
UIImage *newImage = nil;
UIGraphicsBeginImageContext(frame.size);
{
[image drawInRect:CGRectMake(0, 0, frame.size.width, frame.size.height)];
[text drawAtPoint:drawPoint withAttributes:attributes];
newImage = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();
return newImage;
}
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通过颜色生成图片并添加文字
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| +(UIImage *)imageWithText:(NSString *)text
backgroundColor:(UIColor *)backgroundColor
textColor:(UIColor *)textColor
font:(UIFont *)font
size:(CGSize )size{
CGRect frame = CGRectMake(0.0f, 0.0f, size.width, size.height);
NSDictionary *attributes = @{ NSFontAttributeName : font,
NSForegroundColorAttributeName : textColor };
CGRect textFrame = [text boundingRectWithSize:frame.size
options:(NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading)
attributes:attributes
context:nil];
CGPoint frameMidPoint = CGPointMake(CGRectGetMidX(frame), CGRectGetMidY(frame));
CGPoint textFrameMidPoint = CGPointMake(CGRectGetMidX(textFrame), CGRectGetMidY(textFrame));
CGFloat dx = frameMidPoint.x - textFrameMidPoint.x;
CGFloat dy = frameMidPoint.y - textFrameMidPoint.y;
CGPoint drawPoint = CGPointMake(dx, dy);
UIImage *newimage = nil;
UIGraphicsBeginImageContextWithOptions(frame.size, NO, [UIScreen mainScreen].scale);
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, backgroundColor.CGColor);
CGContextFillRect(context, frame);
[text drawAtPoint:drawPoint withAttributes:attributes];
newimage = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();
return newimage;
}
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图片叠加
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| +(void)maskView:(UIImageView *)imageView withImage:(UIImage *)image{
UIImageView *imageViewMask = [[UIImageView alloc] initWithImage:image];
imageViewMask.frame = CGRectMake(0, 0, imageView.frame.size.width, imageView.frame.size.height);
imageView.layer.mask = imageViewMask.layer;
}
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或者使用另外一种方法
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| - (void)drawRect:(CGRect)rect {
UIImage *imageOne = [UIImage imageNamed:@"bubble_min"];
UIImage *imageTwo = [UIImage imageNamed:@"goldengate"];
[imageOne drawInRect:rect];
[imageTwo drawInRect:CGRectInset(rect, 0.0f, 0.0f) blendMode:kCGBlendModeSourceIn alpha:1];
}
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水平旋转图片
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| +(UIImage *)horizontallyFlippedImageFromImage:(UIImage *)image{
return [UIImage imageWithCGImage:image.CGImage
scale:image.scale
orientation:UIImageOrientationUpMirrored];
}
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修改图片颜色
//kCGBlendModeOverlay能保留灰度信息，kCGBlendModeDestinationIn能保留透明度信息
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| + (UIImage *)imageColorChanged:(UIImage *)image
tintColor:(UIColor *)tintColor
blendMode:(CGBlendMode)blendMode{
UIGraphicsBeginImageContextWithOptions(image.size, NO, 0.0f);
[tintColor setFill];
CGRect bounds = CGRectMake(0, 0, image.size.width, image.size.height);
UIRectFill(bounds);
[image drawInRect:bounds blendMode:blendMode alpha:1.0f];
if (blendMode != kCGBlendModeDestinationIn) {
[image drawInRect:bounds blendMode:kCGBlendModeDestinationIn alpha:1.0f];
}
UIImage *tintedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return tintedImage;
}
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方法使用:
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