[英]iOS : Save image with custom resolution
嗨我嘗試捕獲視圖然后將圖像另存為照片庫,但我需要為捕獲的圖像創建自定義分辨率,這是我的代碼但是當應用程序保存圖像時分辨率很低!
UIGraphicsBeginImageContextWithOptions(self.captureView.bounds.size, self.captureView.opaque, 0.0);
[self.captureView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();
CGRect cropRect = CGRectMake(0 ,0 ,1435 ,1435);
CGImageRef imageRef = CGImageCreateWithImageInRect([screenshot CGImage], cropRect);
CGImageRelease(imageRef);
UIImageWriteToSavedPhotosAlbum(screenshot , nil, nil, nil);
UIGraphicsEndImageContext();
但iPhone的分辨率為:320 x 320,視網膜為:640 x 640
如果你能幫助我解決這個問題,我將不勝感激。
你的代碼非常接近。 您需要做的是以自定義分辨率重新渲染屏幕截圖。 我修改了你的代碼來做到這一點:
UIView* captureView = self.view;
/* Capture the screen shoot at native resolution */
UIGraphicsBeginImageContextWithOptions(captureView.bounds.size, captureView.opaque, 0.0);
[captureView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
/* Render the screen shot at custom resolution */
CGRect cropRect = CGRectMake(0 ,0 ,1435 ,1435);
UIGraphicsBeginImageContextWithOptions(cropRect.size, captureView.opaque, 1.0f);
[screenshot drawInRect:cropRect];
UIImage * customScreenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
/* Save to the photo album */
UIImageWriteToSavedPhotosAlbum(customScreenShot , nil, nil, nil);
請注意,如果捕獲視圖不是方形,則圖像將會失真。 保存的圖像將始終為正方形和1435x1435像素。
看看這個答案 。 代碼包括旋轉但是提問者問了同樣的問題:“如何從UIImageView以全分辨率獲取圖像?”
復制的內容(如果刪除或其他):
- (UIImage *)capturedView
{
float imageScale = sqrtf(powf(self.captureView.transform.a, 2.f) + powf(self.captureView.transform.c, 2.f));
CGFloat widthScale = self.captureView.bounds.size.width / self.captureView.image.size.width;
CGFloat heightScale = self.captureView.bounds.size.height / self.captureView.image.size.height;
float contentScale = MIN(widthScale, heightScale);
float effectiveScale = imageScale * contentScale;
CGSize captureSize = CGSizeMake(enclosingView.bounds.size.width / effectiveScale, enclosingView.bounds.size.height / effectiveScale);
NSLog(@"effectiveScale = %0.2f, captureSize = %@", effectiveScale, NSStringFromCGSize(captureSize));
UIGraphicsBeginImageContextWithOptions(captureSize, YES, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextScaleCTM(context, 1/effectiveScale, 1/effectiveScale);
[enclosingView.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
首先在UIImage對象中獲取圖像。 根據您的需要創建您的尺寸並使用以下..
UIImage *image = // you image;
CGSize size;
if ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] &&
([UIScreen mainScreen].scale == 2.0)) {
// RETINA DISPLAY
size = CGSizeMake(640, 640);
}
else {
// Non Ratina device
size = CGSizeMake(320, 320);
}
UIGraphicsBeginImageContext(size);
[image drawInRect:CGRectMake(0, 0, size.width, size.height)];
UIImage *destImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
現在,您將獲得具有新分辨率的destImage
。
希望這是你要找的:)
-(UIImage*)processImageRect:(UIImage*)image:(CGSize)sizeToForm {
// Draw image1
UIGraphicsBeginImageContext(CGSizeMake(sizeToForm.width, sizeToForm.height));
[image drawInRect:CGRectMake(0.0, 0.0, sizeToForm.width, sizeToForm.height)];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
return resultingImage;
}
繼續這可能會解決您的問題。
你可以用它:
UIImageExtras.h
@interface UIImage (Extras)
-(UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize;
@end
UIImageExtras.m
#import "UIImageExtras.h"
@implementation UIImage (Extras)
- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize
{
//Image de base
UIImage *sourceImage = self;
//Image redimenssionnée
UIImage *newImage = nil;
//Taille de l'image de base
CGSize imageSize = sourceImage.size;
//Longueur et largeur
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
//Dimension désirée
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
//Echelle...
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
//Si taille des image est différentes on redimensionne de facon proportionnelle
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
scaleFactor = widthFactor; // scale to fit height
else
scaleFactor = heightFactor; // scale to fit width
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
//Centre l'image
if (widthFactor > heightFactor)
{
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}
else if (widthFactor < heightFactor)
{
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
UIGraphicsBeginImageContext(targetSize);
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
NSLog(@"could not scale image");
UIGraphicsEndImageContext();
return newImage;
}
@end
這對我有用。 我嘗試使用Facebook SDK獲得的圖像http://pulkitgoyal.in/resizing-high-resolution-images-on-ios-without-memory-issues/
我認為ALAssetRepresentation可以幫到你。
CGSize sizePic = CGSizeMake(320, 460);
UIGraphicsBeginImageContext(sizePic);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *imagePic = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(imagePic, nil, nil, nil);
#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>
+ (UIImage *)resizeImage:(UIImage *)image toResolution:(int)resolution {
NSData *imageData = UIImagePNGRepresentation(image);
CGImageSourceRef src = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
CFDictionaryRef options = (__bridge CFDictionaryRef) @{
(id) kCGImageSourceCreateThumbnailWithTransform : @YES,
(id) kCGImageSourceCreateThumbnailFromImageAlways : @YES,
(id) kCGImageSourceThumbnailMaxPixelSize : @(resolution)
};
CGImageRef thumbnail = CGImageSourceCreateThumbnailAtIndex(src, 0, options);
CFRelease(src);
UIImage *img = [[UIImage alloc]initWithCGImage:thumbnail];
return img;
}
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