Fixed alpha preservation when converting 4-channel Mat to UIImage

10 years ago · d647261de2
parent 424c2bddb3
commit d647261de2
1 changed files with 5 additions and 2 deletions
--- a/modules/imgcodecs/src/ios_conversions.mm
+++ b/modules/imgcodecs/src/ios_conversions.mm
@ -66,6 +66,10 @@ UIImage* MatToUIImage(const cv::Mat& image) {
    CGDataProviderRef provider =
            CGDataProviderCreateWithCFData((__bridge CFDataRef)data);

+    // Preserve alpha transparency, if exists
+    bool alpha = cvMat.channels() == 4;
+    CGBitmapInfo bitMapInfo = (alpha ? kCGImageAlphaLast : kCGImageAlphaNone) | kCGBitmapByteOrderDefault;
+
    // Creating CGImage from cv::Mat
    CGImageRef imageRef = CGImageCreate(image.cols,
                                        image.rows,
@ -73,8 +77,7 @@ UIImage* MatToUIImage(const cv::Mat& image) {
                                        8 * image.elemSize(),
                                        image.step.p[0],
                                        colorSpace,
-                                        kCGImageAlphaNone|
-                                        kCGBitmapByteOrderDefault,
+                                        bitmapInfo,
                                        provider,
                                        NULL,
                                        false,