Download Home : Limit scaling of very small images

This CL attempts to limit scaling of very tiny images to a certain factor.
The contents would still be drawn within the rounded rect.
It also separates the full-width image to a different view holder which
would prevent resizing issues of AsyncImageView on reuse.

Bug: 902950
Change-Id: I804ae1ba44db7c875860a395161b5c9eba4e7147
Reviewed-on: https://chromium-review.googlesource.com/c/1297357
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606191}

chrome/android/java/src/org/chromium/chrome/browser/download/home/list/DateOrderedListView.java

@@ -182,6 +182,7 @@ class DateOrderedListView {
             boolean isFullWidthMedia = false;
             switch (ListUtils.getViewTypeForItem(mModel.get(position), mConfig)) {
                 case ListUtils.ViewType.IMAGE:
+                case ListUtils.ViewType.IMAGE_FULL_WIDTH:
                 case ListUtils.ViewType.IN_PROGRESS_IMAGE:
                     outRect.left = mImagePaddingPx;
                     outRect.right = mImagePaddingPx;

chrome/android/java/src/org/chromium/chrome/browser/download/home/list/ListUtils.java

@@ -26,8 +26,8 @@ import java.util.List;
 public class ListUtils {
     /** The potential types of list items that could be displayed. */
     @IntDef({ViewType.DATE, ViewType.IN_PROGRESS, ViewType.GENERIC, ViewType.VIDEO, ViewType.IMAGE,
-            ViewType.CUSTOM_VIEW, ViewType.PREFETCH, ViewType.SECTION_HEADER,
-            ViewType.IN_PROGRESS_VIDEO, ViewType.IN_PROGRESS_IMAGE})
+            ViewType.IMAGE_FULL_WIDTH, ViewType.CUSTOM_VIEW, ViewType.PREFETCH,
+            ViewType.SECTION_HEADER, ViewType.IN_PROGRESS_VIDEO, ViewType.IN_PROGRESS_IMAGE})
     @Retention(RetentionPolicy.SOURCE)
     public @interface ViewType {
         int DATE = 0;
@@ -35,11 +35,12 @@ public class ListUtils {
         int GENERIC = 2;
         int VIDEO = 3;
         int IMAGE = 4;
-        int CUSTOM_VIEW = 5;
-        int PREFETCH = 6;
-        int SECTION_HEADER = 7;
-        int IN_PROGRESS_VIDEO = 8;
-        int IN_PROGRESS_IMAGE = 9;
+        int IMAGE_FULL_WIDTH = 5;
+        int CUSTOM_VIEW = 6;
+        int PREFETCH = 7;
+        int SECTION_HEADER = 8;
+        int IN_PROGRESS_VIDEO = 9;
+        int IN_PROGRESS_IMAGE = 10;
     }
 
     /**
@@ -95,7 +96,9 @@ public class ListUtils {
                 case OfflineItemFilter.FILTER_VIDEO:
                     return inProgress ? ViewType.IN_PROGRESS_VIDEO : ViewType.VIDEO;
                 case OfflineItemFilter.FILTER_IMAGE:
-                    return inProgress ? ViewType.IN_PROGRESS_IMAGE : ViewType.IMAGE;
+                    return inProgress ? ViewType.IN_PROGRESS_IMAGE
+                                      : (offlineItem.spanFullWidth ? ViewType.IMAGE_FULL_WIDTH
+                                                                   : ViewType.IMAGE);
                 // case OfflineItemFilter.FILTER_PAGE:
                 // case OfflineItemFilter.FILTER_AUDIO:
                 // case OfflineItemFilter.FILTER_OTHER:
@@ -142,10 +145,6 @@ public class ListUtils {
      * @see             GridLayoutManager.SpanSizeLookup
      */
     public static int getSpanSize(ListItem item, DownloadManagerUiConfig config, int spanCount) {
-        if (item instanceof OfflineItemListItem && ((OfflineItemListItem) item).spanFullWidth) {
-            return spanCount;
-        }
-
         switch (getViewTypeForItem(item, config)) {
             case ViewType.IMAGE: // Intentional fallthrough.
             case ViewType.IN_PROGRESS_IMAGE:

chrome/android/java/src/org/chromium/chrome/browser/download/home/list/holder/ListItemViewHolder.java

@@ -35,7 +35,8 @@ public abstract class ListItemViewHolder extends ViewHolder {
                 return GenericViewHolder.create(parent);
             case ListUtils.ViewType.VIDEO:
                 return VideoViewHolder.create(parent);
-            case ListUtils.ViewType.IMAGE:
+            case ListUtils.ViewType.IMAGE: // intentional fall-through
+            case ListUtils.ViewType.IMAGE_FULL_WIDTH:
                 return ImageViewHolder.create(parent);
             case ListUtils.ViewType.CUSTOM_VIEW:
                 return new CustomViewHolder(parent);

chrome/android/java/src/org/chromium/chrome/browser/download/home/list/holder/OfflineItemViewHolder.java

@@ -4,10 +4,13 @@
 
 package org.chromium.chrome.browser.download.home.list.holder;
 
+import android.graphics.Bitmap;
+import android.graphics.Matrix;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.support.annotation.CallSuper;
 import android.view.View;
+import android.widget.ImageView;
 
 import org.chromium.chrome.browser.download.home.list.ListItem;
 import org.chromium.chrome.browser.download.home.list.ListProperties;
@@ -23,6 +26,8 @@ import org.chromium.components.offline_items_collection.OfflineItemVisuals;
  * Helper that supports all typical actions for OfflineItems.
  */
 class OfflineItemViewHolder extends ListItemViewHolder implements ListMenuButton.Delegate {
+    private static final float IMAGE_VIEW_MAX_SCALE_FACTOR = 4.f;
+
     /** The {@link View} that visually represents the selected state of this list item. */
     protected final SelectionView mSelectionView;
 
@@ -89,6 +94,10 @@ class OfflineItemViewHolder extends ListItemViewHolder implements ListMenuButton
             mThumbnail.setAsyncImageDrawable((consumer, width, height) -> {
                 return properties.get(ListProperties.PROVIDER_VISUALS)
                         .getVisuals(offlineItem, width, height, (id, visuals) -> {
+                            Matrix matrix = upscaleBitmapIfNecessary(mThumbnail, visuals);
+                            mThumbnail.setImageMatrix(matrix);
+                            mThumbnail.setScaleType(matrix == null ? ImageView.ScaleType.CENTER_CROP
+                                                                   : ImageView.ScaleType.MATRIX);
                             consumer.onResult(onThumbnailRetrieved(visuals));
                         });
             }, offlineItem.id);
@@ -140,4 +149,34 @@ class OfflineItemViewHolder extends ListItemViewHolder implements ListMenuButton
                 || mSelectionView.isInSelectionMode()
                 != properties.get(ListProperties.SELECTION_MODE_ACTIVE);
     }
+
+    private Matrix upscaleBitmapIfNecessary(ImageView view, OfflineItemVisuals visuals) {
+        Bitmap bitmap = visuals == null ? null : visuals.icon;
+        if (bitmap == null) return null;
+
+        float scale = computeScaleFactor(view, bitmap);
+        if (scale <= 1.f) return null;
+
+        // Compute the required matrix to scale and center the bitmap.
+        Matrix matrix = new Matrix();
+        matrix.setScale(scale, scale);
+        matrix.postTranslate((view.getWidth() - scale * bitmap.getWidth()) * 0.5f,
+                (view.getHeight() - scale * bitmap.getHeight()) * 0.5f);
+        return matrix;
+    }
+
+    /**
+     * Computes a scale factor for the bitmap if the bitmap is too small compared to the view
+     * dimensions. The scaled bitmap will be centered inside the view. No scaling if the dimensions
+     * are comparable.
+     */
+    private float computeScaleFactor(ImageView view, Bitmap bitmap) {
+        float widthRatio = (float) view.getWidth() / bitmap.getWidth();
+        float heightRatio = (float) view.getHeight() / bitmap.getHeight();
+
+        if (Math.max(widthRatio, heightRatio) < IMAGE_VIEW_MAX_SCALE_FACTOR) return 1.f;
+
+        float minRequiredScale = Math.min(widthRatio, heightRatio);
+        return Math.min(minRequiredScale, IMAGE_VIEW_MAX_SCALE_FACTOR);
+    }
 }

ui/android/java/src/org/chromium/ui/widget/RoundedCornerImageView.java

@@ -11,6 +11,7 @@ import android.graphics.BitmapShader;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
+import android.graphics.RectF;
 import android.graphics.Shader;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.ColorDrawable;
@@ -32,7 +33,8 @@ import org.chromium.ui.R;
  *      app:cornerRadiusTopStart="8dp"
  *      app:cornerRadiusTopEnd="8dp"
  *      app:cornerRadiusBottomStart="8dp"
- *      app:cornerRadiusBottomEnd="8dp" />
+ *      app:cornerRadiusBottomEnd="8dp"
+ *      app:roundedfillColor="@android:color/white"/>
  *
  * Note : This does not properly handle padding. Padding will not be taken into account when rounded
  * corners are used.
@@ -44,6 +46,9 @@ public class RoundedCornerImageView extends ImageView {
 
     private Paint mFillPaint;
 
+    // Object to avoid allocations during draw calls.
+    private final RectF mTmpRect = new RectF();
+
     // Whether or not to apply the shader, if we have one. This might be set to false if the image
     // is smaller than the view and does not need to have the corners rounded.
     private boolean mApplyShader;
@@ -170,24 +175,43 @@ public class RoundedCornerImageView extends ImageView {
 
         if (drawFill || drawContent) localRoundedRect.resize(getWidth(), getHeight());
 
+        // First, fill the drawing area with the given fill paint.
         if (drawFill) localRoundedRect.draw(canvas, mFillPaint);
 
         if (!drawContent) {
+            // We probably have an unsupported drawable or we don't want rounded corners. Draw
+            // normally and return.
             super.onDraw(canvas);
             return;
         }
 
+        // We have a drawable to draw with rounded corners. Let's first set up the paint.
         if (drawable instanceof ColorDrawable) {
             ColorDrawable colorDrawable = (ColorDrawable) drawable;
             localPaint.setColor(colorDrawable.getColor());
         }
 
         if (mShader != null && mApplyShader) {
+            // Apply the matrix to the bitmap shader.
             mShader.setLocalMatrix(getImageMatrix());
             localPaint.setShader(mShader);
+
+            // Find the desired bounding box where the bitmap is to be shown.
+            mTmpRect.set(getDrawable().getBounds());
+            getImageMatrix().mapRect(mTmpRect);
         }
 
+        final int saveCount = canvas.save();
+
+        // Clip the canvas to the desired bounding box so that the shader isn't applied anywhere
+        // outside the desired area.
+        if (mApplyShader) canvas.clipRect(mTmpRect);
+
+        // Draw the rounded rectangle.
         localRoundedRect.draw(canvas, localPaint);
+
+        // Remove the clip.
+        canvas.restoreToCount(saveCount);
     }
 
     private boolean isSupportedDrawable(Drawable drawable) {