iphone(objective-c)相当于j2me的drawRegion方法 截取部分图片显示到指定位置
图片(UIImage*) img
要截取的起始坐标sx:(int) sx1 sy:(int)sy1
要截取的长度和宽度sw:(int) sw1 sh:(int) sh1
最终要显示的坐标desx:(int) desx1 desy:(int)desy1
-(UIImage*)objectiveDrawRegion:(UIImage*) img sx:(int) sx1 sy:(int)sy1 sw:(int) sw1 sh:(int) sh1 desx:(int) desx1 desy:(int)desy1{
[self saveImage:img name:@"objectiveDrawRegion1.png"];
//创建图片缓冲
void *imageDataRegion=malloc(screenWidth*screenHeight*32);
CGColorSpaceRef iColorSpaceRegion=CGColorSpaceCreateDeviceRGB();
CGContextRef iDeviceRegion=CGBitmapContextCreate(imageDataRegion,screenWidth,screenHeight,8,4*screenWidth,iColorSpaceRegion,kCGImageAlphaPremultipliedLast);
//剪切区域
CGRect clipRegion=CGRectMake(sx1,sy1,sw1,sh1);
CGContextClipToRect(iDeviceRegion, clipRegion);
CGFloat widthf=img.size.width;
CGFloat heightf=img.size.height;
CGRect cg=CGRectMake(0.0, 0.0, widthf, heightf);
//画底图
CGContextDrawImage(iDeviceRegion,cg, img.CGImage);
//将缓冲形成图片
CGImageRef ioffRegion=CGBitmapContextCreateImage(iDeviceRegion);
CGRect cg1=CGRectMake(desx1, desy1, sw1, sh1);
UIImage *ui=[UIImage imageWithCGImage:ioffRegion];
CGContextDrawImage(当前context,cg1, ui.CGImage);
//清除缓冲
CGColorSpaceRelease(iColorSpaceRegion);
CGContextRelease(iDeviceRegion);
CGImageRelease(ioffRegion);
free(imageDataRegion);
// iDeviceRegion=NULL;
// imageDataRegion=0;
return ui;
}
／／这个方法更高效
/*
实现j2me的drawRegion方法
sx 图片剪切的x位置
sy 图片剪切的y位置
sw 图片剪切的宽度
sh 图片剪切的高度
dx 剪切后的x位置
dy 剪切后的y位置
device 上下文
*/
-(void) objectiveDrawRegion:(UIImage*) img
sx:(int) sx1
sy:(int) sy1
sw:(int) sw1
sh:(int) sh1
dx:(int) dx1
dy:(int) dy1
device:(CGContextRef)idevicecopyOffscr
{
CGRect rect = CGRectMake(sx1, sy1, sw1, sh1);
CGImageRef imgRef = CGImageCreateWithImageInRect(img.CGImage, rect);
int dy1Trans = screenHeight - dy1 - sh1;
CGContextDrawImage(idevicecopyOffscr
, CGRectMake(dx1, dy1Trans, sw1, sh1)
, imgRef);
CGImageRelease(imgRef);
｝