無法使用UIGraphics合併兩個圖像，圖像位置不正確

我想製作一個簡單的應用程序，它將相機覆蓋圖與在UIImagePicker中拍攝的照片相結合。在這個例子中，我想將熊耳朵的疊加視圖與照片結合起來。無法使用UIGraphics合併兩個圖像，圖像位置不正確

- (IBAction)pushTakePhoto:(id)sender { 

    UIImagePickerController *picker = [[UIImagePickerController alloc] init]; 
    picker.delegate = self; 
    picker.sourceType = UIImagePickerControllerSourceTypeCamera; 
    picker.cameraDevice=UIImagePickerControllerCameraDeviceFront; 

    //create overlay UIView 
    UIImage *bearEars = [UIImage imageNamed:@"bearEars"]; 
    UIImageView *imageView = [[UIImageView alloc] initWithImage:bearEars]; 

    UIView *camerOverlayView = [[UIView alloc] initWithFrame:imageView.frame]; 
    [camerOverlayView addSubview:imageView]; 


    [picker setCameraOverlayView:camerOverlayView]; 

    [self presentViewController:picker animated:YES completion:NULL]; 


}

上面的代碼創建覆蓋，這工作正常。下面的代碼組合所述圖像：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { 

    UIImage *chosenImage = info[UIImagePickerControllerOriginalImage]; 

    //first we flip the image 
    UIImage * flippedImage = [UIImage imageWithCGImage:chosenImage.CGImage scale:chosenImage.scale orientation:UIImageOrientationLeftMirrored]; 
    chosenImage=flippedImage; 

    //now we need to add the ears 


    //get pics 
    UIImage *backgroundImage = chosenImage; 
    UIImage *watermarkImage = [UIImage imageNamed:@"bearEars"]; 

    //start a workspace 
    UIGraphicsBeginImageContext(backgroundImage.size); 
    [backgroundImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)]; 
    //position seems off for some reason 
    [watermarkImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)]; 
    UIImage *result = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 
    chosenImage=result; 


    self.finalImageView.image = chosenImage; 

    [picker dismissViewControllerAnimated:YES completion:NULL]; 

}

當我結合然而bearEars覆蓋不位於（0,0），但在代替的最終圖像的中間圖像。我不知道爲什麼會發生這種情況。我只是想要它像覆蓋相機視圖中的圖像。任何想法爲什麼發生這種情況？謝謝

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2015-02-07 Kex

我認爲圖像居中，因爲您在drawInRect方法中對兩個圖像使用相同的矩形尺寸。嘗試從backgroundImage.size改變大小watermarkImage.size爲watermarkImage：

[watermarkImage drawInRect:CGRectMake(0, 0, watermarkImage.size.width, watermarkImage.size.height)];

編輯：

爲了做watermarkImage正確的大小，你需要找到一個規模大小 - 從圖像大小差異從最終圖像預覽。您可在繪製過程中watermarkImage除以和backgroundImage的寬度與self.view

CGFloat scale = backgroundImage.size.width/self.view.frame.size.width;

然後你可以使用這個值的寬度，這樣做：

[watermarkImage drawInRect:CGRectMake(0, 0, watermarkImage.size.width * scale, watermarkImage.size.height * scale)];

希望它能幫助。

來源

2015-02-07 09:22:06

我試過了，它只是使watermarkImage小得多，而不是正確的大小 – Kex 2015-02-07 09:41:19

我已經擴大了答案，希望它有幫助 – 2015-02-07 10:38:59

嘿這個作品，現在有道理。謝謝！ – Kex 2015-02-07 11:44:15

無法使用UIGraphics合併兩個圖像，圖像位置不正確

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