Added resizing with keeping aspect ratio when dimension is 0.

picasso/src/main/java/com/squareup/picasso/BitmapHunter.java

@@ -463,12 +463,15 @@ static Bitmap transformResult(Request data, Bitmap result, int exifRotation) {
         float heightRatio = targetHeight / (float) inHeight;
         float scale = widthRatio < heightRatio ? widthRatio : heightRatio;
         matrix.preScale(scale, scale);
-      } else if (targetWidth != 0 && targetHeight != 0 //
+      } else if ((targetWidth != 0 || targetHeight != 0) //
           && (targetWidth != inWidth || targetHeight != inHeight)) {
         // If an explicit target size has been specified and they do not match the results bounds,
         // pre-scale the existing matrix appropriately.
-        float sx = targetWidth / (float) inWidth;
-        float sy = targetHeight / (float) inHeight;
+        // Keep aspect ratio if one dimension is set to 0.
+        float sx = targetWidth != 0 ? targetWidth / (float) inWidth
+            : targetHeight / (float) inHeight;
+        float sy = targetHeight != 0 ? targetHeight / (float) inHeight
+            : targetWidth / (float) inWidth;
         matrix.preScale(sx, sy);
       }
     }

picasso/src/main/java/com/squareup/picasso/Request.java

@@ -157,15 +157,15 @@ String getName() {
   }
 
   public boolean hasSize() {
-    return targetWidth != 0;
+    return targetWidth != 0 || targetHeight != 0;
   }
 
   boolean needsTransformation() {
     return needsMatrixTransform() || hasCustomTransformations();
   }
 
   boolean needsMatrixTransform() {
-    return targetWidth != 0 || rotationDegrees != 0;
+    return hasSize() || rotationDegrees != 0;
   }
 
   boolean hasCustomTransformations() {
@@ -230,7 +230,7 @@ boolean hasImage() {
     }
 
     boolean hasSize() {
-      return targetWidth != 0;
+      return targetWidth != 0 || targetHeight != 0;
     }
 
     boolean hasPriority() {
@@ -265,13 +265,19 @@ public Builder setResourceId(int resourceId) {
       return this;
     }
 
-    /** Resize the image to the specified size in pixels. */
+    /**
+     * Resize the image to the specified size in pixels.
+     * Use 0 as desired dimension to resize keeping aspect ratio.
+     */
     public Builder resize(int targetWidth, int targetHeight) {
-      if (targetWidth <= 0) {
-        throw new IllegalArgumentException("Width must be positive number.");
+      if (targetWidth < 0) {
+        throw new IllegalArgumentException("Width must be positive number or 0.");
+      }
+      if (targetHeight < 0) {
+        throw new IllegalArgumentException("Height must be positive number or 0.");
       }
-      if (targetHeight <= 0) {
-        throw new IllegalArgumentException("Height must be positive number.");
+      if (targetHeight == 0 && targetWidth == 0) {
+        throw new IllegalArgumentException("At least one dimension has to be positive number.");
       }
       this.targetWidth = targetWidth;
       this.targetHeight = targetHeight;
@@ -390,11 +396,13 @@ public Request build() {
       if (centerInside && centerCrop) {
         throw new IllegalStateException("Center crop and center inside can not be used together.");
       }
-      if (centerCrop && targetWidth == 0) {
-        throw new IllegalStateException("Center crop requires calling resize.");
+      if (centerCrop && (targetWidth == 0 || targetHeight == 0)) {
+        throw new IllegalStateException(
+            "Center crop requires calling resize with positive width and height.");
       }
-      if (centerInside && targetWidth == 0) {
-        throw new IllegalStateException("Center inside requires calling resize.");
+      if (centerInside && (targetWidth == 0 || targetHeight == 0)) {
+        throw new IllegalStateException(
+            "Center inside requires calling resize with positive width and height.");
       }
       if (priority == null) {
         priority = Priority.NORMAL;

picasso/src/main/java/com/squareup/picasso/RequestHandler.java

@@ -145,11 +145,19 @@ static void calculateInSampleSize(int reqWidth, int reqHeight, int width, int he
       BitmapFactory.Options options, Request request) {
     int sampleSize = 1;
     if (height > reqHeight || width > reqWidth) {
-      final int heightRatio = (int) Math.floor((float) height / (float) reqHeight);
-      final int widthRatio = (int) Math.floor((float) width / (float) reqWidth);
-      sampleSize = request.centerInside
-          ? Math.max(heightRatio, widthRatio)
-          : Math.min(heightRatio, widthRatio);
+      final int heightRatio;
+      final int widthRatio;
+      if (reqHeight == 0) {
+        sampleSize = (int) Math.floor((float) width / (float) reqWidth);
+      } else if (reqWidth == 0) {
+        sampleSize = (int) Math.floor((float) height / (float) reqHeight);
+      } else {
+        heightRatio = (int) Math.floor((float) height / (float) reqHeight);
+        widthRatio = (int) Math.floor((float) width / (float) reqWidth);
+        sampleSize = request.centerInside
+            ? Math.max(heightRatio, widthRatio)
+            : Math.min(heightRatio, widthRatio);
+      }
     }
     options.inSampleSize = sampleSize;
     options.inJustDecodeBounds = false;

picasso/src/main/java/com/squareup/picasso/Utils.java

@@ -181,7 +181,7 @@ static String createKey(Request data, StringBuilder builder) {
       }
       builder.append('\n');
     }
-    if (data.targetWidth != 0) {
+    if (data.hasSize()) {
       builder.append("resize:").append(data.targetWidth).append('x').append(data.targetHeight);
       builder.append('\n');
     }

picasso/src/test/java/com/squareup/picasso/BitmapHunterTest.java

@@ -405,6 +405,30 @@ public class BitmapHunterTest {
     assertThat(shadowMatrix.getPreOperations()).containsOnly("rotate 90.0");
   }
 
+  @Test public void keepsAspectRationWhileResizingWhenDesiredWidthIs0() throws Exception {
+    Request request = new Request.Builder(URI_1).resize(20, 0).build();
+    Bitmap source = Bitmap.createBitmap(40, 20, ARGB_8888);
+
+    Bitmap result = transformResult(request, source, 0);
+
+    ShadowBitmap shadowBitmap = shadowOf(result);
+    Matrix matrix = shadowBitmap.getCreatedFromMatrix();
+    ShadowMatrix shadowMatrix = shadowOf(matrix);
+    assertThat(shadowMatrix.getPreOperations()).containsOnly("scale 0.5 0.5");
+  }
+
+  @Test public void keepsAspectRationWhileResizingWhenDesiredHeighIs0() throws Exception {
+    Request request = new Request.Builder(URI_1).resize(0, 10).build();
+    Bitmap source = Bitmap.createBitmap(40, 20, ARGB_8888);
+
+    Bitmap result = transformResult(request, source, 0);
+
+    ShadowBitmap shadowBitmap = shadowOf(result);
+    Matrix matrix = shadowBitmap.getCreatedFromMatrix();
+    ShadowMatrix shadowMatrix = shadowOf(matrix);
+    assertThat(shadowMatrix.getPreOperations()).containsOnly("scale 0.5 0.5");
+  }
+
   @Test public void exifRotationWithManualRotation() throws Exception {
     Bitmap source = Bitmap.createBitmap(10, 10, ARGB_8888);
     Request data = new Request.Builder(URI_1).rotate(-45).build();

picasso/src/test/java/com/squareup/picasso/RequestCreatorTest.java

@@ -514,7 +514,31 @@ public void intoRemoteViewsNotificationWithFitThrows() {
     }
   }
 
-  @Test public void appWidgetActionWithDefaultPriority() {
+  @Test
+  public void intoTargetResizeWith0WithCenterInsideOrCenterCropThrows() {
+    try {
+      new RequestCreator(picasso, URI_1, 0).resize(0, 10).centerInside().into(mockTarget());
+      fail("Center inside with unknown width should throw exception.");
+    } catch (IllegalStateException ignored) {
+    }
+    try {
+      new RequestCreator(picasso, URI_1, 0).resize(10, 0).centerInside().into(mockTarget());
+      fail("Center inside with unknown height should throw exception.");
+    } catch (IllegalStateException ignored) {
+    }
+    try {
+      new RequestCreator(picasso, URI_1, 0).resize(0, 10).centerCrop().into(mockTarget());
+      fail("Center inside with unknown width should throw exception.");
+    } catch (IllegalStateException ignored) {
+    }
+    try {
+      new RequestCreator(picasso, URI_1, 0).resize(10, 0).centerCrop().into(mockTarget());
+      fail("Center inside with unknown height should throw exception.");
+    } catch (IllegalStateException ignored) {
+    }
+  }
+
+  @Test public void appWidgetActionWithDefaultPriority() throws Exception {
     new RequestCreator(picasso, URI_1, 0).into(mockRemoteViews(), 0, new int[] { 1, 2, 3 });
     verify(picasso).enqueueAndSubmit(actionCaptor.capture());
     assertThat(actionCaptor.getValue().getPriority()).isEqualTo(NORMAL);
@@ -578,13 +602,8 @@ public void intoRemoteViewsNotificationWithFitThrows() {
     } catch (IllegalArgumentException ignored) {
     }
     try {
-      new RequestCreator().resize(0, 10);
-      fail("Zero width should throw exception.");
-    } catch (IllegalArgumentException ignored) {
-    }
-    try {
-      new RequestCreator().resize(10, 0);
-      fail("Zero height should throw exception.");
+      new RequestCreator().resize(0, 0);
+      fail("Zero dimensions should throw exception.");
     } catch (IllegalArgumentException ignored) {
     }
   }

picasso/src/test/java/com/squareup/picasso/RequestHandlerTest.java

@@ -73,6 +73,20 @@ public class RequestHandlerTest {
     assertThat(options.inSampleSize).isEqualTo(4);
   }
 
+  @Test public void calculateInSampleSizeKeepAspectRatioWithWidth() {
+    final BitmapFactory.Options options = new BitmapFactory.Options();
+    Request data = new Request.Builder(URI_1).resize(400, 0).build();
+    calculateInSampleSize(data.targetWidth, data.targetHeight, 800, 200, options, data);
+    assertThat(options.inSampleSize).isEqualTo(2);
+  }
+
+  @Test public void calculateInSampleSizeKeepAspectRatioWithHeight() {
+    final BitmapFactory.Options options = new BitmapFactory.Options();
+    Request data = new Request.Builder(URI_1).resize(0, 100).build();
+    calculateInSampleSize(data.targetWidth, data.targetHeight, 800, 200, options, data);
+    assertThat(options.inSampleSize).isEqualTo(2);
+  }
+
   @Test public void nullBitmapOptionsIfNoResizing() {
     // No resize must return no bitmap options
     final Request noResize = new Request.Builder(URI_1).build();