180 lines
7.5 KiB
Objective-C
180 lines
7.5 KiB
Objective-C
/*
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File: ImageHelpers.m
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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Inc. ("Apple") in consideration of your agreement to the following
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terms, and your use, installation, modification or redistribution of
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this Apple software constitutes acceptance of these terms. If you do
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not agree with these terms, please do not use, install, modify or
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redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and
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subject to these terms, Apple grants you a personal, non-exclusive
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license, under Apple's copyrights in this original Apple software (the
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"Apple Software"), to use, reproduce, modify and redistribute the Apple
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Software, with or without modifications, in source and/or binary forms;
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provided that if you redistribute the Apple Software in its entirety and
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without modifications, you must retain this notice and the following
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text and disclaimers in all such redistributions of the Apple Software.
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Neither the name, trademarks, service marks or logos of Apple Inc. may
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be used to endorse or promote products derived from the Apple Software
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without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or
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implied, are granted by Apple herein, including but not limited to any
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patent rights that may be infringed by your derivative works or by other
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works in which the Apple Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Copyright (C) 2009 Apple Inc. All Rights Reserved.
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*/
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#include "ImageHelpers.h"
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const CGBitmapInfo kDefaultCGBitmapInfo = (kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host);
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const CGBitmapInfo kDefaultCGBitmapInfoNoAlpha = (kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Host);
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CGColorSpaceRef GetDeviceRGBColorSpace() {
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static CGColorSpaceRef deviceRGBSpace = NULL;
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if( deviceRGBSpace == NULL )
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deviceRGBSpace = CGColorSpaceCreateDeviceRGB();
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return deviceRGBSpace;
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}
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float GetScaleForProportionalResize( CGSize theSize, CGSize intoSize, bool onlyScaleDown, bool maximize )
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{
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float sx = theSize.width;
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float sy = theSize.height;
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float dx = intoSize.width;
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float dy = intoSize.height;
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float scale = 1;
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if( sx != 0 && sy != 0 )
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{
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dx = dx / sx;
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dy = dy / sy;
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// if maximize is true, take LARGER of the scales, else smaller
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if( maximize ) scale = (dx > dy) ? dx : dy;
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else scale = (dx < dy) ? dx : dy;
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if( scale > 1 && onlyScaleDown ) // reset scale
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scale = 1;
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}
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else
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{
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scale = 0;
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}
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return scale;
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}
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CGContextRef CreateCGBitmapContextForWidthAndHeight( unsigned int width, unsigned int height,
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CGColorSpaceRef optionalColorSpace, CGBitmapInfo optionalInfo )
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{
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CGColorSpaceRef colorSpace = (optionalColorSpace == NULL) ? GetDeviceRGBColorSpace() : optionalColorSpace;
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CGBitmapInfo alphaInfo = ( (int32_t)optionalInfo < 0 ) ? kDefaultCGBitmapInfo : optionalInfo;
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return CGBitmapContextCreate( NULL, width, height, 8, 0, colorSpace, alphaInfo );
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}
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CGImageRef CreateCGImageFromUIImageScaled( UIImage* image, float scaleFactor )
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{
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CGImageRef newImage = NULL;
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CGContextRef bmContext = NULL;
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BOOL mustTransform = YES;
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CGAffineTransform transform = CGAffineTransformIdentity;
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UIImageOrientation orientation = image.imageOrientation;
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CGImageRef srcCGImage = CGImageRetain( image.CGImage );
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size_t width = CGImageGetWidth(srcCGImage) * scaleFactor;
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size_t height = CGImageGetHeight(srcCGImage) * scaleFactor;
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// These Orientations are rotated 0 or 180 degrees, so they retain the width/height of the image
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if( (orientation == UIImageOrientationUp) || (orientation == UIImageOrientationDown) || (orientation == UIImageOrientationUpMirrored) || (orientation == UIImageOrientationDownMirrored) )
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{
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bmContext = CreateCGBitmapContextForWidthAndHeight( width, height, NULL, kDefaultCGBitmapInfo );
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}
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else // The other Orientations are rotated ±90 degrees, so they swap width & height.
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{
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bmContext = CreateCGBitmapContextForWidthAndHeight( height, width, NULL, kDefaultCGBitmapInfo );
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}
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//CGContextSetInterpolationQuality( bmContext, kCGInterpolationLow );
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CGContextSetBlendMode( bmContext, kCGBlendModeCopy ); // we just want to copy the data
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switch(orientation)
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{
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case UIImageOrientationDown: // 0th row is at the bottom, and 0th column is on the right - Rotate 180 degrees
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transform = CGAffineTransformMake(-1.0, 0.0, 0.0, -1.0, width, height);
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break;
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case UIImageOrientationLeft: // 0th row is on the left, and 0th column is the bottom - Rotate -90 degrees
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transform = CGAffineTransformMake(0.0, 1.0, -1.0, 0.0, height, 0.0);
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break;
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case UIImageOrientationRight: // 0th row is on the right, and 0th column is the top - Rotate 90 degrees
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transform = CGAffineTransformMake(0.0, -1.0, 1.0, 0.0, 0.0, width);
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break;
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case UIImageOrientationUpMirrored: // 0th row is at the top, and 0th column is on the right - Flip Horizontal
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transform = CGAffineTransformMake(-1.0, 0.0, 0.0, 1.0, width, 0.0);
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break;
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case UIImageOrientationDownMirrored: // 0th row is at the bottom, and 0th column is on the left - Flip Vertical
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transform = CGAffineTransformMake(1.0, 0.0, 0, -1.0, 0.0, height);
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break;
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case UIImageOrientationLeftMirrored: // 0th row is on the left, and 0th column is the top - Rotate -90 degrees and Flip Vertical
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transform = CGAffineTransformMake(0.0, -1.0, -1.0, 0.0, height, width);
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break;
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case UIImageOrientationRightMirrored: // 0th row is on the right, and 0th column is the bottom - Rotate 90 degrees and Flip Vertical
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transform = CGAffineTransformMake(0.0, 1.0, 1.0, 0.0, 0.0, 0.0);
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break;
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default:
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mustTransform = NO;
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break;
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}
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if( mustTransform ) CGContextConcatCTM( bmContext, transform );
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CGContextDrawImage( bmContext, CGRectMake(0.0, 0.0, width, height), srcCGImage );
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CGImageRelease( srcCGImage );
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newImage = CGBitmapContextCreateImage( bmContext );
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CFRelease( bmContext );
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return newImage;
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}
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@implementation UIImage (scale)
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-(UIImage*) scaleToSize:(CGSize)toSize
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{
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UIImage *scaledImg = nil;
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float scale = GetScaleForProportionalResize( self.size, toSize, false, false );
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CGImageRef cgImage = CreateCGImageFromUIImageScaled( self, scale );
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if( cgImage )
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{
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scaledImg = [UIImage imageWithCGImage:cgImage]; // autoreleased
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CGImageRelease( cgImage );
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}
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return scaledImg;
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}
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@end
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