Scale drag previews with the screen zoom

If you have zoomed your layout, which is going to be common when
designing for 10" screens, then the drag preview shown when dragging
from the palette is not sized correctly. It assumes a 100% zoom.

This changeset looks at the current canvas zoom and scales the preview
image such that it matches the canvas zoom, so if you're zoomed in
then the preview will be larger, and vice versa.

Change-Id: I471b4d8ae459aad79d50a2b54ecca6bd7d7cf943

3 files changed, 70 insertions, 6 deletions

diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtils.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtils.java
index 94419b3..6432aa4 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtils.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtils.java
@@ -19,8 +19,11 @@ import com.android.ide.common.api.Rect;
 
 import org.eclipse.swt.graphics.Rectangle;
 
+import java.awt.AlphaComposite;
+import java.awt.Color;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
+import java.awt.RenderingHints;
 import java.awt.image.BufferedImage;
 import java.awt.image.DataBufferInt;
 import java.util.Iterator;
@@ -427,4 +430,31 @@ public class ImageUtils {
         throw new NumberFormatException();
     }
 
+    /**
+     * Resize the given image
+     *
+     * @param source the image to be scaled
+     * @param xScale x scale
+     * @param yScale y scale
+     * @return the scaled image
+     */
+    public static BufferedImage scale(BufferedImage source, double xScale, double yScale) {
+        int sourceWidth = source.getWidth();
+        int sourceHeight = source.getHeight();
+        int destWidth = (int) (xScale * sourceWidth);
+        int destHeight = (int) (yScale * sourceHeight);
+        BufferedImage scaled = new BufferedImage(destWidth, destHeight, source.getType());
+        Graphics2D g2 = scaled.createGraphics();
+        g2.setComposite(AlphaComposite.Src);
+        g2.setColor(new Color(0, true));
+        g2.fillRect(0, 0, destWidth, destHeight);
+        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
+                RenderingHints.VALUE_INTERPOLATION_BILINEAR);
+        g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
+        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+        g2.drawImage(source, 0, 0, destWidth, destHeight, 0, 0, sourceWidth, sourceHeight, null);
+        g2.dispose();
+
+        return scaled;
+    }
 }
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 fdc559d..00604d6 100755
--- 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
@@ -27,9 +27,9 @@ import com.android.ide.common.api.Rect;
 import com.android.ide.common.rendering.LayoutLibrary;
 import com.android.ide.common.rendering.api.Capability;
 import com.android.ide.common.rendering.api.LayoutLog;
-import com.android.ide.common.rendering.api.Params.RenderingMode;
 import com.android.ide.common.rendering.api.RenderSession;
 import com.android.ide.common.rendering.api.ViewInfo;
+import com.android.ide.common.rendering.api.Params.RenderingMode;
 import com.android.ide.eclipse.adt.internal.editors.IconFactory;
 import com.android.ide.eclipse.adt.internal.editors.descriptors.DocumentDescriptor;
 import com.android.ide.eclipse.adt.internal.editors.descriptors.ElementDescriptor;
@@ -567,10 +567,14 @@ public class PaletteControl extends Composite {
             createDragImage(e);
             if (mImage != null && !mIsPlaceholder) {
                 ImageData data = mImage.getImageData();
-                int width = data.width;
-                int height = data.height;
+                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);
                 bounds = new Rect(0, 0, width, height);
-                dragBounds = new Rect(-width / 2, -height / 2, width, height);
+                dragBounds = new Rect(x, y, width, height);
             }
 
             SimpleElement se = new SimpleElement(
@@ -828,6 +832,11 @@ public class PaletteControl extends Composite {
                                     !hasTransparency ? 0.6f : needsContrast ? 0.8f : 0.7f/*alpha*/,
                                     0x000000 /* shadowRgb */);
 
+                            double scale = canvas.getScale();
+                            if (scale != 1L) {
+                                cropped = ImageUtils.scale(cropped, scale, scale);
+                            }
+
                             Display display = getDisplay();
                             int alpha = (!hasTransparency || !needsContrast) ? IMG_ALPHA : -1;
                             Image swtImage = SwtUtils.convertToSwt(display, cropped, true, alpha);
diff --git a/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtilsTest.java b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtilsTest.java
index 73129f4..f903e74 100644
--- a/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtilsTest.java
+++ b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ImageUtilsTest.java
@@ -291,11 +291,11 @@ public class ImageUtilsTest extends TestCase {
         assertEquals(0xFFFF0000, sub.getRGB(0, 0));
         assertEquals(0xFFFF0000, sub.getRGB(9, 9));
 
-        sub = ImageUtils.subImage(image, 23, 23, 5, 5);
+        sub = ImageUtils.subImage(image, 23, 23, 23 + 5, 23 + 5);
         assertEquals(5, sub.getWidth());
         assertEquals(5, sub.getHeight());
         assertEquals(0xFF00FF00, sub.getRGB(0, 0));
-        assertEquals(0xFFFF0000, sub.getRGB(9, 9));
+        assertEquals(0xFFFF0000, sub.getRGB(4, 4));
     }
 
     public void testGetColor() throws Exception {
@@ -303,4 +303,29 @@ public class ImageUtilsTest extends TestCase {
         assertEquals(0xFF000000, ImageUtils.getColor("#000000"));
         assertEquals(0xABCDEF91, ImageUtils.getColor("#ABCDEF91"));
     }
+
+    public void testScaleImage() throws Exception {
+        BufferedImage image = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB_PRE);
+        Graphics g = image.getGraphics();
+        g.setColor(new Color(0xFF00FF00, true));
+        g.fillRect(0, 0, image.getWidth(), image.getHeight());
+        g.setColor(new Color(0xFFFF0000, true));
+        g.fillRect(25, 25, 50, 50);
+        g.dispose();
+
+        BufferedImage scaled = ImageUtils.scale(image, 0.5, 0.5);
+        assertEquals(50, scaled.getWidth());
+        assertEquals(50, scaled.getHeight());
+        assertEquals(0xFF00FF00, scaled.getRGB(0, 0));
+        assertEquals(0xFF00FF00, scaled.getRGB(49, 49));
+        assertEquals(0xFFFF0000, scaled.getRGB(25, 25));
+
+        scaled = ImageUtils.scale(image, 2.0, 2.0);
+        assertEquals(200, scaled.getWidth());
+        assertEquals(200, scaled.getHeight());
+        assertEquals(0xFF00FF00, scaled.getRGB(0, 0));
+        assertEquals(0xFF00FF00, scaled.getRGB(48, 48));
+        assertEquals(0xFFFF0000, scaled.getRGB(100, 100));
+        assertEquals(0xFF00FF00, scaled.getRGB(199, 199));
+    }
 }