feat: Preserve Aspect Ratio Option

example/src/App.tsx

@@ -20,8 +20,8 @@ import { createSkiaImageFromData } from './SkiaUtils';
 
 type PixelFormat = Options<'uint8'>['pixelFormat'];
 
-const WIDTH = 480;
-const HEIGHT = 640;
+const WIDTH = 300;
+const HEIGHT = 300;
 const TARGET_TYPE = 'uint8' as const;
 const TARGET_FORMAT: PixelFormat = 'rgba';
 
@@ -39,8 +39,13 @@ export default function App() {
   const updatePreviewImageFromData = useRunOnJS(
     (data: SkData, pixelFormat: PixelFormat) => {
       const image = createSkiaImageFromData(data, WIDTH, HEIGHT, pixelFormat);
+      if (image == null) {
+        data.dispose();
+        return;
+      }
       previewImage.value?.dispose();
       previewImage.value = image;
+      data.dispose();
     },
     []
   );
@@ -64,11 +69,10 @@ export default function App() {
 
       const data = Skia.Data.fromBytes(result);
       updatePreviewImageFromData(data, TARGET_FORMAT);
-      data.dispose();
       const end = performance.now();
 
       console.log(
-        `Resized ${frame.width}x${frame.height} into 100x100 frame (${
+        `Resized ${frame.width}x${frame.height} into ${WIDTH}x${HEIGHT} frame (${
           result.length
         }) in ${(end - start).toFixed(2)}ms`
       );
@@ -119,5 +123,7 @@ const styles = StyleSheet.create({
     position: 'absolute',
     bottom: 80,
     left: 20,
+    borderColor: '#F00',
+    borderWidth: 2,
   },
 });

ios/ResizePlugin.mm

@@ -289,7 +289,7 @@ - (FrameBuffer*)convertFrameToARGB:(Frame*)frame {
   return _argbBuffer;
 }
 
-- (FrameBuffer*)resizeARGB:(FrameBuffer*)buffer crop:(CGRect)crop scale:(CGSize)scale {
+- (FrameBuffer*)resizeARGB:(FrameBuffer*)buffer crop:(CGRect)crop scale:(CGSize)scale preserveAspectRatio:(BOOL)preserveAspectRatio {
   CGFloat cropWidth = crop.size.width;
   CGFloat cropHeight = crop.size.height;
   CGFloat cropX = crop.origin.x;
@@ -327,20 +327,44 @@ - (FrameBuffer*)resizeARGB:(FrameBuffer*)buffer crop:(CGRect)crop scale:(CGSize)
     }
   }
 
-  // Crop
-  vImage_Buffer cropped = (vImage_Buffer){.data = AdvancePtr(source->data, cropY * source->rowBytes + cropX * buffer.bytesPerPixel),
-                                          .height = (unsigned long)cropHeight,
-                                          .width = (unsigned long)cropWidth,
-                                          .rowBytes = source->rowBytes};
-  source = &cropped;
-
-  // Resize
-  vImage_Error error = vImageScale_ARGB8888(source, destination, _tempResizeBuffer, kvImageNoFlags);
-  if (error != kvImageNoError) {
-    [[unlikely]];
-    @throw [NSException exceptionWithName:@"Resize Error"
-                                   reason:[NSString stringWithFormat:@"Failed to resize ARGB buffer! Error: %zu", error]
-                                 userInfo:nil];
+
+  if (!preserveAspectRatio) {
+    // Crop
+    vImage_Buffer cropped = (vImage_Buffer){.data = AdvancePtr(source->data, cropY * source->rowBytes + cropX * buffer.bytesPerPixel),
+        .height = (unsigned long)cropHeight,
+        .width = (unsigned long)cropWidth,
+      .rowBytes = source->rowBytes};
+    source = &cropped;
+
+    // Resize
+    vImage_Error error = vImageScale_ARGB8888(source, destination, _tempResizeBuffer, kvImageNoFlags);
+    if (error != kvImageNoError) {
+      [[unlikely]];
+      @throw [NSException exceptionWithName:@"Resize Error"
+                                     reason:[NSString stringWithFormat:@"Failed to resize ARGB buffer! Error: %zu", error]
+                                   userInfo:nil];
+    }
+  }
+  else {
+    // Transform and pad
+    CGFloat scaleFactor = MIN(scale.width / buffer.width, scale.height / buffer.height);
+    CGAffineTransform cgTransform = CGAffineTransformIdentity;
+    cgTransform = CGAffineTransformScale(cgTransform, scaleFactor, scaleFactor);
+    vImage_AffineTransform vTransform = vImage_AffineTransform();
+    vTransform.a = cgTransform.a;
+    vTransform.b = cgTransform.b;
+    vTransform.c = cgTransform.c;
+    vTransform.d = cgTransform.d;
+    vTransform.tx = cgTransform.tx;
+    vTransform.ty = cgTransform.ty;
+    const Pixel_8888 backgroundColor = {255, 0, 0, 0};
+    vImage_Error error = vImageAffineWarp_ARGB8888(source, destination, nil, &vTransform, backgroundColor, kvImageBackgroundColorFill);
+    if (error != kvImageNoError) {
+      [[unlikely]];
+      @throw [NSException exceptionWithName:@"Resize Error"
+                                     reason:[NSString stringWithFormat:@"Failed to resize ARGB buffer! Error: %zu", error]
+                                   userInfo:nil];
+    }
   }
 
   return _resizeBuffer;
@@ -520,6 +544,13 @@ - (id)callback:(Frame*)frame withArguments:(NSDictionary*)arguments {
     mirror = [mirrorParam boolValue];
   }
   NSLog(@"ResizePlugin: Mirror: %@", mirror ? @"YES" : @"NO");
+
+  NSNumber* preserveAspectRatioParam = arguments[@"preserveAspectRatio"];
+  BOOL preserveAspectRatio = NO;
+  if (preserveAspectRatioParam != nil) {
+    preserveAspectRatio = [preserveAspectRatioParam boolValue];
+  }
+  NSLog(@"ResizePlugin: Preserve Aspect Ratio: %@", preserveAspectRatio ? @"YES" : @"NO");
 
   double cropWidth = (double)frame.width;
   double cropHeight = (double)frame.height;
@@ -592,7 +623,7 @@ - (id)callback:(Frame*)frame withArguments:(NSDictionary*)arguments {
   // 3. Resize
   CGRect cropRect = CGRectMake(cropX, cropY, cropWidth, cropHeight);
   CGSize scaleSize = CGSizeMake(scaleWidth, scaleHeight);
-  result = [self resizeARGB:result crop:cropRect scale:scaleSize];
+  result = [self resizeARGB:result crop:cropRect scale:scaleSize preserveAspectRatio:preserveAspectRatio];
 
   // 4. Rotate
   result = [self rotateARGBBuffer:result rotation:rotation];

src/index.ts

@@ -45,6 +45,11 @@ export interface Options<T extends DataType> {
    * Scale the image to the given target size. This is applied after cropping.
    */
   scale?: Size;
+  /**
+   * If set to `true`, the image will be resized to to fit within the dimensions specified by
+   * scale and padded, maintaining the aspect ratio of the original image.
+   */
+  preserveAspectRatio?: boolean;
   /**
    * Rotate the image by a given amount of degrees, clockwise.
    * @default '0deg'