Fix bounds computation for drags from palette to canvas

When you drag over the canvas, the potential drop location is shown
along with an outline of the component as it would appear at that
location. This relies on knowing the size of the dragged component.

When dragging from the palette we use the drag preview image. However,
the bounds were a bit too big because we were using the raw size of
the drag image, and it now includes a drop shadow!  This changeset
adjusts this such that we use the original ViewInfo bounds from the
render rather than the usually larger image bounds.

Change-Id: Ic4b870995e17284fbd8a7ed2f4b4a7ec02f4e2c3

diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/PaletteControl.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/PaletteControl.java
index 78e906c..89e02df 100755 (executable)
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/PaletteControl.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/PaletteControl.java
@@ -641,13 +641,16 @@ public class PaletteControl extends Composite {
 
             createDragImage(e);
             if (mImage != null && !mIsPlaceholder) {
-                ImageData data = mImage.getImageData();
+                int imageWidth = mImageLayoutBounds.width;
+                int imageHeight = mImageLayoutBounds.height;
+                assert mImageLayoutBounds.x == 0;
+                assert mImageLayoutBounds.y == 0;
                 LayoutCanvas canvas = mEditor.getCanvasControl();
                 double scale = canvas.getScale();
-                int x = -data.width / 2;
-                int y = -data.height / 2;
-                int width = (int) (data.width / scale);
-                int height = (int) (data.height / scale);
+                int x = -imageWidth / 2;
+                int y = -imageHeight / 2;
+                int width = (int) (imageWidth / scale);
+                int height = (int) (imageHeight / scale);
                 bounds = new Rect(0, 0, width, height);
                 dragBounds = new Rect(x, y, width, height);
             }
@@ -713,8 +716,10 @@ public class PaletteControl extends Composite {
         /** Amount of alpha to multiply into the image (divided by 256) */
         private static final int IMG_ALPHA = 216;
 
-        /** The image shown by the drag source effect */
+        /** The image shown during the drag */
         private Image mImage;
+        /** The non-effect bounds of the drag image */
+        private Rectangle mImageLayoutBounds;
 
         /**
          * If true, the image is a preview of the view, and if not it is a "fallback"
@@ -723,7 +728,14 @@ public class PaletteControl extends Composite {
         private boolean mIsPlaceholder;
 
         private void createDragImage(DragSourceEvent event) {
-            mImage = renderPreview();
+            Pair<Image, Rectangle> preview = renderPreview();
+            if (preview != null) {
+                mImage = preview.getFirst();
+                mImageLayoutBounds = preview.getSecond();
+            } else {
+                mImage = null;
+                mImageLayoutBounds = null;
+            }
 
             mIsPlaceholder = mImage == null;
             if (mIsPlaceholder) {
@@ -769,8 +781,11 @@ public class PaletteControl extends Composite {
             }
         }
 
-        /** Performs the actual rendering of the descriptor into an image */
-        private Image renderPreview() {
+        /**
+         * Performs the actual rendering of the descriptor into an image and returns the
+         * image as well as the layout bounds of the image (not including drop shadow etc)
+         */
+        private Pair<Image, Rectangle> renderPreview() {
             ViewMetadataRepository repository = ViewMetadataRepository.get();
             RenderMode renderMode = repository.getRenderMode(mDesc.getFullClassName());
             if (renderMode == RenderMode.SKIP) {
@@ -922,6 +937,8 @@ public class PaletteControl extends Composite {
                         }
 
                         if (cropped != null) {
+                            int width = initialCrop != null ? initialCrop.w : cropped.getWidth();
+                            int height = initialCrop != null ? initialCrop.h : cropped.getHeight();
                             boolean needsContrast = hasTransparency
                                     && !ImageUtils.containsDarkPixels(cropped);
                             cropped = ImageUtils.createDropShadow(cropped,
@@ -937,7 +954,8 @@ public class PaletteControl extends Composite {
                             Display display = getDisplay();
                             int alpha = (!hasTransparency || !needsContrast) ? IMG_ALPHA : -1;
                             Image swtImage = SwtUtils.convertToSwt(display, cropped, true, alpha);
-                            return swtImage;
+                            Rectangle imageBounds = new Rectangle(0, 0, width, height);
+                            return Pair.of(swtImage, imageBounds);
                         }
                     }
                 }