[Fix]MetalView scale calculation (#61)

Author: ipavlidakis

sdk/objc/components/renderer/metal/RTCMTLVideoView.m

@@ -137,25 +137,13 @@ - (void)setMultipleTouchEnabled:(BOOL)multipleTouchEnabled {
 }
 #endif
 
-- (CGFloat)currentScaleFactor {
-  CGFloat scale = 1.0;
-#if TARGET_OS_IPHONE
-  scale = [UIScreen mainScreen].scale;
-#elif TARGET_OS_OSX
-  scale = [NSScreen mainScreen].backingScaleFactor;
-#endif
-  return MAX(scale, 1.0);
-}
-
 - (void)performLayout {
   CGRect bounds = self.bounds;
   self.metalView.frame = bounds;
   if (!CGSizeEqualToSize(self.videoFrameSize, CGSizeZero)) {
     self.metalView.drawableSize = [self drawableSize];
   } else {
-    // Apply scale factor for default size as well (when videoFrameSize is zero)
-    CGFloat scale = [self currentScaleFactor];
-    self.metalView.drawableSize = CGSizeMake(bounds.size.width * scale, bounds.size.height * scale);
+    self.metalView.drawableSize = bounds.size;
   }
 }
 
@@ -258,16 +246,11 @@ - (CGSize)drawableSize {
   BOOL sizeIsLandscape = (self.videoFrame.rotation == RTC_OBJC_TYPE(RTCVideoRotation_0)) ||
       (self.videoFrame.rotation == RTC_OBJC_TYPE(RTCVideoRotation_180));
 
-  CGSize size;
   if (useLandscape == sizeIsLandscape) {
-    size = videoFrameSize;
+    return videoFrameSize;
   } else {
-    size = CGSizeMake(videoFrameSize.height, videoFrameSize.width);
+    return CGSizeMake(videoFrameSize.height, videoFrameSize.width);
   }
-  
-  // Apply scale factor for retina displays
-  CGFloat scale = [self currentScaleFactor];
-  return CGSizeMake(size.width * scale, size.height * scale);
 }
 
 #pragma mark - RTC_OBJC_TYPE(RTCVideoRenderer)