Fixes scaling on android and added aspect ratio (#70)

README.md

@@ -154,10 +154,10 @@ p, q, r, s, t
 #### Scale
 
 ```dart
-ScaleOption(width,height);
+ScaleOption(width, height, keepRatio: keepRatio);
 ```
 
-After specifying the width and height, it is not clipped, but stretched to the specified width and height (Does not maintain the aspect ratio of the image).
+After specifying the width and height, it is not clipped, but stretched to the specified width and height (Does maintain the aspect ratio of the image if wanted).
 
 #### AddText
 

android/src/main/kotlin/top/kikt/flutter_image_editor/core/ImageHandler.kt

@@ -49,27 +49,29 @@ class ImageHandler(private var bitmap: Bitmap) {
   }
 
   private fun handleScale(option: ScaleOption): Bitmap {
-    val w = min(bitmap.width, option.width)
-    val h = min(bitmap.height, option.height)
-
+    val bitmapRatio = bitmap.width.toFloat() / bitmap.height.toFloat()
+    val optionRatio = option.width.toFloat() / option.height.toFloat()
+    var w = option.width
+    var h = option.height
+    if (option.keepRatio) {
+      if (bitmapRatio < optionRatio) {
+        w = (option.height * bitmapRatio).toInt()
+      } else if (bitmapRatio > optionRatio) {
+        h = (option.width / bitmapRatio).toInt()
+      }
+    }
     val newBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888)
-
     val canvas = Canvas(newBitmap)
-
     val p = Paint()
-
     val m = Matrix()
-
     val width: Int = bitmap.width
     val height: Int = bitmap.height
     if (width != w || height != h) {
       val sx: Float = w / width.toFloat()
       val sy: Float = h / height.toFloat()
       m.setScale(sx, sy)
     }
-
     canvas.drawBitmap(bitmap, m, p)
-
     return newBitmap
   }
 

android/src/main/kotlin/top/kikt/flutter_image_editor/option/ScaleOption.kt

@@ -1,3 +1,3 @@
 package top.kikt.flutter_image_editor.option
 
-data class ScaleOption(val width: Int, val height: Int) : Option
+data class ScaleOption(val width: Int, val height: Int, val keepRatio: Boolean) : Option

android/src/main/kotlin/top/kikt/flutter_image_editor/util/ConvertUtils.kt

@@ -120,7 +120,8 @@ object ConvertUtils {
 
     val w = optionMap["width"] as Int
     val h = optionMap["height"] as Int
-    return ScaleOption(w, h)
+    val keepRatio = optionMap["keepRatio"] as Boolean
+    return ScaleOption(w, h, keepRatio)
   }
 
   private fun getColorOption(optionMap: Any?): ColorOption {

ios/Classes/FIConvertUtils.h

@@ -54,6 +54,7 @@ NS_ASSUME_NONNULL_BEGIN
 @interface FIScaleOption : NSObject <FIOption>
 @property(assign, nonatomic) int width;
 @property(assign, nonatomic) int height;
+@property(assign, nonatomic) BOOL keepRatio;
 @end
 
 @interface FIAddText : NSObject <FIOption>

ios/Classes/FIConvertUtils.m

@@ -106,6 +106,7 @@ + (id)createFromDict:(NSDictionary *)dict {
   FIScaleOption *option = [FIScaleOption new];
   option.width = [dict[@"width"] intValue];
   option.height = [dict[@"height"] intValue];
+  option.keepRatio = [dict[@"keepRatio"] boolValue];
   return option;
 }
 

ios/Classes/FIUIImageHandler.m

@@ -249,14 +249,27 @@ - (void)scale:(FIScaleOption *)option {
     return;
   }
 
-  UIGraphicsBeginImageContext(CGSizeMake(option.width, option.height));
+  float imageRatio = outImage.size.width / outImage.size.height;
+  float optionRatio = option.width / option.height;
+  int w = option.width;
+  int h = option.height;
+
+  if (option.keepRatio) {
+    if (imageRatio < optionRatio) {
+      w = option.height * imageRatio;
+    } else if (imageRatio > optionRatio) {
+      h = option.width / imageRatio;
+    }
+  }
+
+  UIGraphicsBeginImageContext(CGSizeMake(w, h));
 
   CGContextRef ctx = UIGraphicsGetCurrentContext();
   if (!ctx) {
     return;
   }
 
-  [outImage drawInRect:CGRectMake(0, 0, option.width, option.height)];
+  [outImage drawInRect:CGRectMake(0, 0, w, h)];
 
   UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
 

lib/src/option/scale.dart

@@ -3,10 +3,13 @@ part of 'edit_options.dart';
 class ScaleOption implements Option {
   final int width;
   final int height;
+  final bool keepRatio;
 
-  ScaleOption(this.width, this.height)
-      : assert(width > 0),
-        assert(height > 0);
+  ScaleOption(
+    this.width,
+    this.height, {
+    this.keepRatio: false,
+  }) : assert(width > 0 && height > 0);
 
   @override
   bool get canIgnore => false;
@@ -15,8 +18,11 @@ class ScaleOption implements Option {
   String get key => 'scale';
 
   @override
-  Map<String, Object> get transferValue => {
-        'width': width,
-        'height': height,
-      };
+  Map<String, Object> get transferValue {
+    return <String, Object>{
+      'width': width,
+      'height': height,
+      'keepRatio': keepRatio,
+    };
+  }
 }