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//
// UIImage+Helper.m
// CXA
//
// Created by Xummer on 14-3-3.
// Copyright (c) 2014年 Xummer. All rights reserved.
//
#import "UIImage+Helper.h"
@implementation UIImage (Helper)
// if newImage's width or heigth < 1, image will be cliped
+ (UIImage *)getThumbnailImage:(UIImage *)image withMaxLen:(CGFloat)maxLen
{
CGFloat imageMaxLen, imageMinLen;
BOOL widthIsLarger = image.size.width > image.size.height;
if (widthIsLarger) {
imageMaxLen = image.size.width;
imageMinLen = image.size.height;
}
else {
imageMaxLen = image.size.height;
imageMinLen = image.size.width;
}
if (imageMaxLen > maxLen) {
CGFloat scaleFloat = maxLen/imageMaxLen;
CGFloat newImgMinL = imageMinLen * scaleFloat;
CGSize size;
if (newImgMinL < 1) {
scaleFloat = 1/imageMinLen;
if (widthIsLarger) {
size = CGSizeMake(maxLen, image.size.height * scaleFloat);
}
else {
size = CGSizeMake(image.size.width * scaleFloat, maxLen);
}
}
else {
size = CGSizeMake(image.size.width * scaleFloat,
image.size.height * scaleFloat);
}
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformScale(transform, scaleFloat, scaleFloat);
CGContextConcatCTM(context, transform);
// Draw the image into the transformed context and return the image
[image drawAtPoint:CGPointMake(0.0f, 0.0f)];
UIImage *newimg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newimg;
}
else{
return image;
}
}
- (UIImage *)thumbnailWithMaxLen:(CGFloat)maxLen {
return [[self class] getThumbnailImage:self withMaxLen:maxLen];
}
- (UIImage *)imageWithTintColor:(UIColor *)tintColor {
return [self imageWithTintColor:tintColor blendMode:kCGBlendModeDestinationIn];
}
- (UIImage *)imageWithGradientTintColor:(UIColor *)tintColor {
return [self imageWithTintColor:tintColor blendMode:kCGBlendModeOverlay];
}
- (UIImage *)imageWithTintColor:(UIColor *)tintColor blendMode:(CGBlendMode)blendMode
{
//We want to keep alpha, set opaque to NO; Use 0.0f for scale to use the scale factor of the device’s main screen.
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);
[tintColor setFill];
CGRect bounds = CGRectMake(0, 0, self.size.width, self.size.height);
UIRectFill(bounds);
//Draw the tinted image in context
[self drawInRect:bounds blendMode:blendMode alpha:1.0f];
if (blendMode != kCGBlendModeDestinationIn) {
[self drawInRect:bounds blendMode:kCGBlendModeDestinationIn alpha:1.0f];
}
UIImage *tintedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return tintedImage;
}
@end
@implementation UIImage (Color)
typedef enum {
ALPHA = 0,
BLUE = 1,
GREEN = 2,
RED = 3
} PIXELS;
+ (UIImage *)imageWithColor:(UIColor *)color {
CGRect rect = CGRectMake(0.0f,0.0f,1.0f,1.0f);
return [[self class] imageWithColor:color andRect:rect];
}
+ (UIImage *)imageWithColor:(UIColor *)color andRect:(CGRect)rect {
UIGraphicsBeginImageContext(rect.size);
CGContextRef context =UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context,[color CGColor]);
CGContextFillRect(context, rect);
UIImage *image =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
+ (UIImage *)imageWithColor:(UIColor *)color andSize:(CGSize)size {
return [[self class] imageWithColor:color andRect:(CGRect){
.origin = CGPointZero,
.size = size
}];
}
- (UIImage *)greyScaleImage {
CGSize size = [self size];
int width = size.width;
int height = size.height;
// the pixels will be painted to this array
uint32_t *pixels = (uint32_t *) malloc(width * height * sizeof(uint32_t));
// clear the pixels so any transparency is preserved
memset(pixels, 0, width * height * sizeof(uint32_t));
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// create a context with RGBA pixels
CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, width * sizeof(uint32_t), colorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast);
// paint the bitmap to our context which will fill in the pixels array
CGContextDrawImage(context, CGRectMake(0, 0, width, height), [self CGImage]);
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
uint8_t *rgbaPixel = (uint8_t *) &pixels[y * width + x];
// convert to grayscale using recommended method: http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale
uint32_t gray = 0.3 * rgbaPixel[RED] + 0.59 * rgbaPixel[GREEN] + 0.11 * rgbaPixel[BLUE];
// set the pixels to gray
rgbaPixel[RED] = gray;
rgbaPixel[GREEN] = gray;
rgbaPixel[BLUE] = gray;
}
}
// create a new CGImageRef from our context with the modified pixels
CGImageRef image = CGBitmapContextCreateImage(context);
// we're done with the context, color space, and pixels
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
free(pixels);
// make a new UIImage to return
UIImage *resultUIImage = [UIImage imageWithCGImage:image];
// we're done with image now too
CGImageRelease(image);
return resultUIImage;
}
@end