如何将 UIView 转换为 UIImage？答案

【问题标题】：How to convert UIView as UIImage?如何将 UIView 转换为 UIImage？
【发布时间】：2011-07-25 01:41:38
【问题描述】：

我正在从 currentview 截取屏幕截图。但我想设置框架……不想将全视图转换为图像。我给了框架大小……但它总是需要图片为全视图..有什么帮助吗？

            CGRect rectt = CGRectMake(100, 150,150,200);
    UIGraphicsBeginImageContext(rectt.size);
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageView *imgView = [[UIImageView alloc] initWithFrame:rectt];

【问题讨论】：

标签： iphone ipad ios4 iphone-sdk-3.0 cgcontext

【解决方案1】：

尝试使用这个子类：

// code to use the capture:
    // in .h : #import "CaptureView.h"
    CaptureView *cloneView = [[CaptureView alloc] initWithView:scrollView ];
    [scrollView addSubview:cloneView];

使用此文件代码

对于 CaptureView.h：

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
#import <QuartzCore/CALayer.h>


@interface CaptureView : UIView {
@private
    UIImage *_imageCapture;
}

@property(nonatomic, retain) UIImage *imageCapture;

// Init
- (id)initWithView:(UIView *)view;

@end

对于 CaptureView.m：

#import "CaptureView.h"

// Private
@interface CaptureView (/* Private */)
- (void)settingImageFromView:(UIView *)view;
@end

// Public
@implementation CaptureView

@synthesize imageCapture = _imageCapture;

// Standard
- (id)initWithFrame:(CGRect)frame {

    if ((self = [super initWithFrame:frame])) {
        // Initialization code.
    }
    return self;
}

// Init
- (id)initWithView:(UIView *)view {
//    if ((self = [super initWithFrame:[view frame]])) {
    if ((self = [super initWithFrame: CGRectMake(0, 0,150,200)])) {
        // Initialization code.
        [self settingImageFromView:view];
    }
    return self;  
}


- (void)settingImageFromView:(UIView *)view {
//    CGRect rect = [view bounds];  
    CGRect rect = CGRectMake(100, 150,150,200);  
    UIGraphicsBeginImageContext(rect.size);  
    CGContextRef context = UIGraphicsGetCurrentContext();  
    [view.layer renderInContext:context];  
    UIImage *imageCaptureRect;

    imageCaptureRect = UIGraphicsGetImageFromCurrentImageContext();  
    _imageCapture = imageCaptureRect;
//    _imageCapture = UIGraphicsGetImageFromCurrentImageContext();  
//    [_imageCapture retain];
    UIGraphicsEndImageContext();   
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code.
    CGPoint accPoint = CGPointMake(0,0);
    [_imageCapture drawAtPoint:accPoint];
}


- (void)dealloc {
    [_imageCapture release];
    [super dealloc];
}

@end

【讨论】：

这段代码运行良好。一个小的改进是自动读取源 UIView 的宽度和高度： CGRect rect = CGRectMake(0, 0, view.frame.size.width, view.frame.size.height);
这个崩溃就像一个魅力

【解决方案2】：

quartz 可能对你有帮助...看看creating image from part of image.... 它不是您问题的直接解决方案，但我认为您可以对其进行调整以满足您的需求..

【讨论】：