android/graphics/Canvas_Delegate.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.graphics;

import com.android.layoutlib.bridge.Bridge;
import com.android.layoutlib.bridge.impl.DelegateManager;
import com.android.layoutlib.bridge.impl.GcSnapshot;

import android.graphics.Paint_Delegate.FontInfo;
import android.text.TextUtils;

import java.awt.Color;
import java.awt.Composite;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.util.List;


/**
 * Delegate implementing the native methods of android.graphics.Canvas
 *
 * Through the layoutlib_create tool, the original native methods of Canvas have been replaced
 * by calls to methods of the same name in this delegate class.
 *
 * This class behaves like the original native implementation, but in Java, keeping previously
 * native data into its own objects and mapping them to int that are sent back and forth between
 * it and the original Canvas class.
 *
 * @see DelegateManager
 *
 */
public final class Canvas_Delegate {

    // ---- delegate manager ----
    private static final DelegateManager<Canvas_Delegate> sManager =
            new DelegateManager<Canvas_Delegate>();

    // ---- delegate helper data ----

    // ---- delegate data ----
    private BufferedImage mBufferedImage;
    private GcSnapshot mSnapshot;

    // ---- Public Helper methods ----

    /**
     * Returns the native delegate associated to a given {@link Canvas} object.
     */
    public static Canvas_Delegate getDelegate(Canvas canvas) {
        return sManager.getDelegate(canvas.mNativeCanvas);
    }

    /**
     * Returns the native delegate associated to a given an int referencing a {@link Canvas} object.
     */
    public static Canvas_Delegate getDelegate(int native_canvas) {
        return sManager.getDelegate(native_canvas);
    }

    /**
     * Returns the current {@link Graphics2D} used to draw.
     */
    public GcSnapshot getSnapshot() {
        return mSnapshot;
    }

    // ---- native methods ----

    /*package*/ static boolean isOpaque(Canvas thisCanvas) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static int getWidth(Canvas thisCanvas) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.mBufferedImage.getWidth();
    }

    /*package*/ static int getHeight(Canvas thisCanvas) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.mBufferedImage.getHeight();
    }

    /*package*/ static void translate(Canvas thisCanvas, float dx, float dy) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.getSnapshot().translate(dx, dy);
    }

    /*package*/ static void rotate(Canvas thisCanvas, float degrees) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.getSnapshot().rotate(Math.toRadians(degrees));
    }

    /*package*/ static void scale(Canvas thisCanvas, float sx, float sy) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.getSnapshot().scale(sx, sy);
    }

    /*package*/ static void skew(Canvas thisCanvas, float kx, float ky) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        // get the current top graphics2D object.
        GcSnapshot g = canvasDelegate.getSnapshot();

        // get its current matrix
        AffineTransform currentTx = g.getTransform();
        // get the AffineTransform for the given skew.
        float[] mtx = Matrix_Delegate.getSkew(kx, ky);
        AffineTransform matrixTx = Matrix_Delegate.getAffineTransform(mtx);

        // combine them so that the given matrix is applied after.
        currentTx.preConcatenate(matrixTx);

        // give it to the graphics2D as a new matrix replacing all previous transform
        g.setTransform(currentTx);
    }

    /*package*/ static boolean clipRect(Canvas thisCanvas, RectF rect) {
        return clipRect(thisCanvas, rect.left, rect.top, rect.right, rect.bottom);
    }

    /*package*/ static boolean clipRect(Canvas thisCanvas, Rect rect) {
        return clipRect(thisCanvas, (float) rect.left, (float) rect.top,
                (float) rect.right, (float) rect.bottom);
    }

    /*package*/ static boolean clipRect(Canvas thisCanvas, float left, float top, float right,
            float bottom) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return false;
        }

        return canvasDelegate.clipRect(left, top, right, bottom, Region.Op.INTERSECT.nativeInt);
    }

    /*package*/ static boolean clipRect(Canvas thisCanvas, int left, int top, int right,
            int bottom) {

        return clipRect(thisCanvas, (float) left, (float) top, (float) right, (float) bottom);
    }

    /*package*/ static int save(Canvas thisCanvas) {
        return save(thisCanvas, Canvas.MATRIX_SAVE_FLAG | Canvas.CLIP_SAVE_FLAG);
    }

    /*package*/ static int save(Canvas thisCanvas, int saveFlags) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.save(saveFlags);
    }

    /*package*/ static void restore(Canvas thisCanvas) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.restore();
    }

    /*package*/ static int getSaveCount(Canvas thisCanvas) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.getSnapshot().size();
    }

    /*package*/ static void restoreToCount(Canvas thisCanvas, int saveCount) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(thisCanvas.mNativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.restoreTo(saveCount);
    }

    /*package*/ static void drawPoints(Canvas thisCanvas, float[] pts, int offset, int count,
            Paint paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void drawPoint(Canvas thisCanvas, float x, float y, Paint paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void drawLines(Canvas thisCanvas,
            final float[] pts, final int offset, final int count,
            Paint paint) {
        draw(thisCanvas.mNativeCanvas, paint.mNativePaint, false /*compositeOnly*/,
                new GcSnapshot.Drawable() {
                    public void draw(Graphics2D graphics, Paint_Delegate paint) {
                        for (int i = 0 ; i < count ; i += 4) {
                            graphics.drawLine((int)pts[i + offset], (int)pts[i + offset + 1],
                                    (int)pts[i + offset + 2], (int)pts[i + offset + 3]);
                        }
                    }
                });
    }

    /*package*/ static void freeCaches() {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static int initRaster(int nativeBitmapOrZero) {
        if (nativeBitmapOrZero > 0) {
            // get the Bitmap from the int
            Bitmap_Delegate bitmapDelegate = Bitmap_Delegate.getDelegate(nativeBitmapOrZero);

            // create a new Canvas_Delegate with the given bitmap and return its new native int.
            Canvas_Delegate newDelegate = new Canvas_Delegate(bitmapDelegate.getImage());

            return sManager.addDelegate(newDelegate);
        } else {
            // create a new Canvas_Delegate and return its new native int.
            Canvas_Delegate newDelegate = new Canvas_Delegate();

            return sManager.addDelegate(newDelegate);
        }
    }

    /*package*/ static void native_setBitmap(int nativeCanvas, int bitmap) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        // get the delegate from the native int.
        Bitmap_Delegate bitmapDelegate = Bitmap_Delegate.getDelegate(bitmap);
        if (bitmapDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.setBitmap(bitmapDelegate.getImage());
    }

    /*package*/ static int native_saveLayer(int nativeCanvas, RectF bounds,
                                               int paint, int layerFlags) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        Paint_Delegate paintDelegate = Paint_Delegate.getDelegate(paint);
        if (paintDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.saveLayer(bounds, paintDelegate, layerFlags);
    }

    /*package*/ static int native_saveLayer(int nativeCanvas, float l,
                                               float t, float r, float b,
                                               int paint, int layerFlags) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        Paint_Delegate paintDelegate = Paint_Delegate.getDelegate(paint);
        if (paintDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.saveLayer(new RectF(l, t, r, b),
                paintDelegate, layerFlags);
    }

    /*package*/ static int native_saveLayerAlpha(int nativeCanvas,
                                                    RectF bounds, int alpha,
                                                    int layerFlags) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.saveLayerAlpha(bounds, alpha, layerFlags);
    }

    /*package*/ static int native_saveLayerAlpha(int nativeCanvas, float l,
                                                    float t, float r, float b,
                                                    int alpha, int layerFlags) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return 0;
        }

        return canvasDelegate.saveLayerAlpha(new RectF(l, t, r, b), alpha, layerFlags);
    }


    /*package*/ static void native_concat(int nCanvas, int nMatrix) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        Matrix_Delegate matrixDelegate = Matrix_Delegate.getDelegate(nMatrix);
        if (matrixDelegate == null) {
            assert false;
            return;
        }

        // get the current top graphics2D object.
        GcSnapshot snapshot = canvasDelegate.getSnapshot();

        // get its current matrix
        AffineTransform currentTx = snapshot.getTransform();
        // get the AffineTransform of the given matrix
        AffineTransform matrixTx = matrixDelegate.getAffineTransform();

        // combine them so that the given matrix is applied after.
        currentTx.preConcatenate(matrixTx);

        // give it to the graphics2D as a new matrix replacing all previous transform
        snapshot.setTransform(currentTx);
    }

    /*package*/ static void native_setMatrix(int nCanvas, int nMatrix) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nCanvas);
        if (canvasDelegate == null) {
            assert false;
        }

        Matrix_Delegate matrixDelegate = Matrix_Delegate.getDelegate(nMatrix);
        if (matrixDelegate == null) {
            assert false;
        }

        // get the current top graphics2D object.
        GcSnapshot snapshot = canvasDelegate.getSnapshot();

        // get the AffineTransform of the given matrix
        AffineTransform matrixTx = matrixDelegate.getAffineTransform();

        // give it to the graphics2D as a new matrix replacing all previous transform
        snapshot.setTransform(matrixTx);

        if (matrixDelegate.hasPerspective()) {
            assert false;
            Bridge.getLog().fidelityWarning(null,
                    "android.graphics.Canvas#setMatrix(android.graphics.Matrix) only " +
                    "supports affine transformations in the Layout Preview.", null);
        }
    }

    /*package*/ static boolean native_clipRect(int nCanvas,
                                                  float left, float top,
                                                  float right, float bottom,
                                                  int regionOp) {

        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nCanvas);
        if (canvasDelegate == null) {
            assert false;
        }

        return canvasDelegate.clipRect(left, top, right, bottom, regionOp);
    }

    /*package*/ static boolean native_clipPath(int nativeCanvas,
                                                  int nativePath,
                                                  int regionOp) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static boolean native_clipRegion(int nativeCanvas,
                                                    int nativeRegion,
                                                    int regionOp) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void nativeSetDrawFilter(int nativeCanvas,
                                                   int nativeFilter) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static boolean native_getClipBounds(int nativeCanvas,
                                                       Rect bounds) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return false;
        }

        Rectangle rect = canvasDelegate.getSnapshot().getClip().getBounds();
        if (rect != null) {
            bounds.left = rect.x;
            bounds.top = rect.y;
            bounds.right = rect.x + rect.width;
            bounds.bottom = rect.y + rect.height;
            return true;
        }
        return false;
    }

    /*package*/ static void native_getCTM(int canvas, int matrix) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static boolean native_quickReject(int nativeCanvas,
                                                     RectF rect,
                                                     int native_edgeType) {
        // FIXME properly implement quickReject
        return false;
    }

    /*package*/ static boolean native_quickReject(int nativeCanvas,
                                                     int path,
                                                     int native_edgeType) {
        // FIXME properly implement quickReject
        return false;
    }

    /*package*/ static boolean native_quickReject(int nativeCanvas,
                                                     float left, float top,
                                                     float right, float bottom,
                                                     int native_edgeType) {
        // FIXME properly implement quickReject
        return false;
    }

    /*package*/ static void native_drawRGB(int nativeCanvas, int r, int g, int b) {
        native_drawColor(nativeCanvas, 0xFF000000 | r << 16 | (g&0xFF) << 8 | (b&0xFF),
                PorterDuff.Mode.SRC_OVER.nativeInt);

    }

    /*package*/ static void native_drawARGB(int nativeCanvas, int a, int r, int g, int b) {
        native_drawColor(nativeCanvas, a << 24 | (r&0xFF) << 16 | (g&0xFF) << 8 | (b&0xFF),
                PorterDuff.Mode.SRC_OVER.nativeInt);
    }

    /*package*/ static void native_drawColor(int nativeCanvas, int color) {
        native_drawColor(nativeCanvas, color, PorterDuff.Mode.SRC_OVER.nativeInt);
    }

    /*package*/ static void native_drawColor(int nativeCanvas, final int color, final int mode) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        final int w = canvasDelegate.mBufferedImage.getWidth();
        final int h = canvasDelegate.mBufferedImage.getHeight();
        draw(nativeCanvas, new GcSnapshot.Drawable() {

            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                // reset its transform just in case
                graphics.setTransform(new AffineTransform());

                // set the color
                graphics.setColor(new Color(color, true /*alpha*/));

                Composite composite = PorterDuffXfermode_Delegate.getComposite(
                        PorterDuffXfermode_Delegate.getPorterDuffMode(mode), 0xFF);
                if (composite != null) {
                    graphics.setComposite(composite);
                }

                graphics.fillRect(0, 0, w, h);
            }
        });
    }

    /*package*/ static void native_drawPaint(int nativeCanvas, int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawLine(int nativeCanvas,
            final float startX, final float startY, final float stopX, final float stopY,
            int paint) {

        draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {
            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                graphics.drawLine((int)startX, (int)startY, (int)stopX, (int)stopY);
            }
        });
    }

    /*package*/ static void native_drawRect(int nativeCanvas, RectF rect,
                                               int paint) {
        native_drawRect(nativeCanvas, rect.left, rect.top, rect.right, rect.bottom, paint);
    }

    /*package*/ static void native_drawRect(int nativeCanvas,
            final float left, final float top, final float right, final float bottom, int paint) {

        draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {
            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                int style = paint.getStyle();

                // draw
                if (style == Paint.Style.FILL.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.fillRect((int)left, (int)top, (int)(right-left), (int)(bottom-top));
                }

                if (style == Paint.Style.STROKE.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.drawRect((int)left, (int)top, (int)(right-left), (int)(bottom-top));
                }
            }
        });
    }

    /*package*/ static void native_drawOval(int nativeCanvas, final RectF oval, int paint) {
        if (oval.right > oval.left && oval.bottom > oval.top) {
            draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {
                public void draw(Graphics2D graphics, Paint_Delegate paint) {
                    int style = paint.getStyle();

                    // draw
                    if (style == Paint.Style.FILL.nativeInt ||
                            style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                        graphics.fillOval((int)oval.left, (int)oval.top,
                                (int)oval.width(), (int)oval.height());
                    }

                    if (style == Paint.Style.STROKE.nativeInt ||
                            style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                        graphics.drawOval((int)oval.left, (int)oval.top,
                                (int)oval.width(), (int)oval.height());
                    }
                }
            });
        }
    }

    /*package*/ static void native_drawCircle(int nativeCanvas, float cx,
                                                 float cy, float radius,
                                                 int paint) {
        native_drawOval(nativeCanvas,
                new RectF(cx - radius, cy - radius, radius*2, radius*2),
                paint);
    }

    /*package*/ static void native_drawArc(int nativeCanvas, RectF oval,
                                              float startAngle, float sweep,
                                              boolean useCenter, int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawRoundRect(int nativeCanvas,
            final RectF rect, final float rx, final float ry, int paint) {

        draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {

            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                int style = paint.getStyle();

                // draw
                if (style == Paint.Style.FILL.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.fillRoundRect(
                            (int)rect.left, (int)rect.top, (int)rect.width(), (int)rect.height(),
                            (int)rx, (int)ry);
                }

                if (style == Paint.Style.STROKE.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.drawRoundRect(
                            (int)rect.left, (int)rect.top, (int)rect.width(), (int)rect.height(),
                            (int)rx, (int)ry);
                }
            }
        });
    }

    /*package*/ static void native_drawPath(int nativeCanvas, int path,
                                               int paint) {
        final Path_Delegate pathDelegate = Path_Delegate.getDelegate(path);
        if (pathDelegate == null) {
            assert false;
            return;
        }

        draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {
            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                Shape shape = pathDelegate.getJavaShape();
                int style = paint.getStyle();

                if (style == Paint.Style.FILL.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.fill(shape);
                }

                if (style == Paint.Style.STROKE.nativeInt ||
                        style == Paint.Style.FILL_AND_STROKE.nativeInt) {
                    graphics.draw(shape);
                }
            }
        });
    }

    /*package*/ static void native_drawBitmap(Canvas thisCanvas, int nativeCanvas, int bitmap,
                                                 float left, float top,
                                                 int nativePaintOrZero,
                                                 int canvasDensity,
                                                 int screenDensity,
                                                 int bitmapDensity) {
        // get the delegate from the native int.
        Bitmap_Delegate bitmapDelegate = Bitmap_Delegate.getDelegate(bitmap);
        if (bitmapDelegate == null) {
            assert false;
            return;
        }

        BufferedImage image = bitmapDelegate.getImage();
        float right = left + image.getWidth();
        float bottom = top + image.getHeight();

        drawBitmap(nativeCanvas, image, bitmapDelegate.getConfig(), nativePaintOrZero,
                0, 0, image.getWidth(), image.getHeight(),
                (int)left, (int)top, (int)right, (int)bottom);
    }

    /*package*/ static void native_drawBitmap(Canvas thisCanvas, int nativeCanvas, int bitmap,
                                                 Rect src, RectF dst,
                                                 int nativePaintOrZero,
                                                 int screenDensity,
                                                 int bitmapDensity) {
        // get the delegate from the native int.
        Bitmap_Delegate bitmapDelegate = Bitmap_Delegate.getDelegate(bitmap);
        if (bitmapDelegate == null) {
            assert false;
            return;
        }

        BufferedImage image = bitmapDelegate.getImage();

        if (src == null) {
            drawBitmap(nativeCanvas, image, bitmapDelegate.getConfig(), nativePaintOrZero,
                    0, 0, image.getWidth(), image.getHeight(),
                    (int)dst.left, (int)dst.top, (int)dst.right, (int)dst.bottom);
        } else {
            drawBitmap(nativeCanvas, image, bitmapDelegate.getConfig(), nativePaintOrZero,
                    src.left, src.top, src.width(), src.height(),
                    (int)dst.left, (int)dst.top, (int)dst.right, (int)dst.bottom);
        }
    }

    /*package*/ static void native_drawBitmap(int nativeCanvas, int bitmap,
                                                 Rect src, Rect dst,
                                                 int nativePaintOrZero,
                                                 int screenDensity,
                                                 int bitmapDensity) {
        // get the delegate from the native int.
        Bitmap_Delegate bitmapDelegate = Bitmap_Delegate.getDelegate(bitmap);
        if (bitmapDelegate == null) {
            assert false;
            return;
        }

        BufferedImage image = bitmapDelegate.getImage();

        if (src == null) {
            drawBitmap(nativeCanvas, image, bitmapDelegate.getConfig(), nativePaintOrZero,
                    0, 0, image.getWidth(), image.getHeight(),
                    dst.left, dst.top, dst.right, dst.bottom);
        } else {
            drawBitmap(nativeCanvas, image, bitmapDelegate.getConfig(), nativePaintOrZero,
                    src.left, src.top, src.width(), src.height(),
                    dst.left, dst.top, dst.right, dst.bottom);
        }
    }

    /*package*/ static void native_drawBitmap(int nativeCanvas, int[] colors,
                                                int offset, int stride, float x,
                                                 float y, int width, int height,
                                                 boolean hasAlpha,
                                                 int nativePaintOrZero) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void nativeDrawBitmapMatrix(int nCanvas, int nBitmap,
                                                      int nMatrix, int nPaint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void nativeDrawBitmapMesh(int nCanvas, int nBitmap,
                                                    int meshWidth, int meshHeight,
                                                    float[] verts, int vertOffset,
                                                    int[] colors, int colorOffset, int nPaint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void nativeDrawVertices(int nCanvas, int mode, int n,
                   float[] verts, int vertOffset, float[] texs, int texOffset,
                   int[] colors, int colorOffset, short[] indices,
                   int indexOffset, int indexCount, int nPaint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawText(int nativeCanvas,
            final char[] text, final int index, final int count,
            final float startX, final float startY, int flags, int paint) {
        draw(nativeCanvas, paint, false /*compositeOnly*/, new GcSnapshot.Drawable() {

            public void draw(Graphics2D graphics, Paint_Delegate paint) {
                // WARNING: the logic in this method is similar to Paint.measureText.
                // Any change to this method should be reflected in Paint.measureText
                // Paint.TextAlign indicates how the text is positioned relative to X.
                // LEFT is the default and there's nothing to do.
                float x = startX;
                float y = startY;
                if (paint.getTextAlign() != Paint.Align.LEFT.nativeInt) {
                    float m = paint.measureText(text, index, count);
                    if (paint.getTextAlign() == Paint.Align.CENTER.nativeInt) {
                        x -= m / 2;
                    } else if (paint.getTextAlign() == Paint.Align.RIGHT.nativeInt) {
                        x -= m;
                    }
                }

                List<FontInfo> fonts = paint.getFonts();

                if (fonts.size() > 0) {
                    FontInfo mainFont = fonts.get(0);
                    int i = index;
                    int lastIndex = index + count;
                    while (i < lastIndex) {
                        // always start with the main font.
                        int upTo = mainFont.mFont.canDisplayUpTo(text, i, lastIndex);
                        if (upTo == -1) {
                            // draw all the rest and exit.
                            graphics.setFont(mainFont.mFont);
                            graphics.drawChars(text, i, lastIndex - i, (int)x, (int)y);
                            return;
                        } else if (upTo > 0) {
                            // draw what's possible
                            graphics.setFont(mainFont.mFont);
                            graphics.drawChars(text, i, upTo - i, (int)x, (int)y);

                            // compute the width that was drawn to increase x
                            x += mainFont.mMetrics.charsWidth(text, i, upTo - i);

                            // move index to the first non displayed char.
                            i = upTo;

                            // don't call continue at this point. Since it is certain the main font
                            // cannot display the font a index upTo (now ==i), we move on to the
                            // fallback fonts directly.
                        }

                        // no char supported, attempt to read the next char(s) with the
                        // fallback font. In this case we only test the first character
                        // and then go back to test with the main font.
                        // Special test for 2-char characters.
                        boolean foundFont = false;
                        for (int f = 1 ; f < fonts.size() ; f++) {
                            FontInfo fontInfo = fonts.get(f);

                            // need to check that the font can display the character. We test
                            // differently if the char is a high surrogate.
                            int charCount = Character.isHighSurrogate(text[i]) ? 2 : 1;
                            upTo = fontInfo.mFont.canDisplayUpTo(text, i, i + charCount);
                            if (upTo == -1) {
                                // draw that char
                                graphics.setFont(fontInfo.mFont);
                                graphics.drawChars(text, i, charCount, (int)x, (int)y);

                                // update x
                                x += fontInfo.mMetrics.charsWidth(text, i, charCount);

                                // update the index in the text, and move on
                                i += charCount;
                                foundFont = true;
                                break;

                            }
                        }

                        // in case no font can display the char, display it with the main font.
                        // (it'll put a square probably)
                        if (foundFont == false) {
                            int charCount = Character.isHighSurrogate(text[i]) ? 2 : 1;

                            graphics.setFont(mainFont.mFont);
                            graphics.drawChars(text, i, charCount, (int)x, (int)y);

                            // measure it to advance x
                            x += mainFont.mMetrics.charsWidth(text, i, charCount);

                            // and move to the next chars.
                            i += charCount;
                        }
                    }
                }
            }
        });
    }

    /*package*/ static void native_drawText(int nativeCanvas, String text,
                                               int start, int end, float x,
                                               float y, int flags, int paint) {
        int count = end - start;
        char[] buffer = TemporaryBuffer.obtain(count);
        TextUtils.getChars(text, start, end, buffer, 0);

        native_drawText(nativeCanvas, buffer, 0, count, x, y, flags, paint);
    }

    /*package*/ static void native_drawTextRun(int nativeCanvas, String text,
            int start, int end, int contextStart, int contextEnd,
            float x, float y, int flags, int paint) {
        int count = end - start;
        char[] buffer = TemporaryBuffer.obtain(count);
        TextUtils.getChars(text, start, end, buffer, 0);

        native_drawText(nativeCanvas, buffer, start, end, x, y, flags, paint);
    }

    /*package*/ static void native_drawTextRun(int nativeCanvas, char[] text,
            int start, int count, int contextStart, int contextCount,
            float x, float y, int flags, int paint) {
        native_drawText(nativeCanvas, text, 0, count, x, y, flags, paint);
    }

    /*package*/ static void native_drawPosText(int nativeCanvas,
                                                  char[] text, int index,
                                                  int count, float[] pos,
                                                  int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawPosText(int nativeCanvas,
                                                  String text, float[] pos,
                                                  int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawTextOnPath(int nativeCanvas,
                                                     char[] text, int index,
                                                     int count, int path,
                                                     float hOffset,
                                                     float vOffset, int bidiFlags,
                                                     int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawTextOnPath(int nativeCanvas,
                                                     String text, int path,
                                                     float hOffset,
                                                     float vOffset,
                                                     int flags, int paint) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void native_drawPicture(int nativeCanvas,
                                                  int nativePicture) {
        // FIXME
        throw new UnsupportedOperationException();
    }

    /*package*/ static void finalizer(int nativeCanvas) {
        // get the delegate from the native int so that it can be disposed.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.dispose();

        // remove it from the manager.
        sManager.removeDelegate(nativeCanvas);
    }

    // ---- Private delegate/helper methods ----

    /**
     * Executes a {@link Drawable} with a given canvas and paint.
     * <p>Note that the drawable may actually be executed several times if there are
     * layers involved (see {@link #saveLayer(RectF, int, int)}.
     */
    private static void draw(int nCanvas, int nPaint, boolean compositeOnly,
            GcSnapshot.Drawable drawable) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        // paint could be 0 meaning no paint
        Paint_Delegate paintDelegate = null;
        if (nPaint > 0) {
            paintDelegate = Paint_Delegate.getDelegate(nPaint);
            if (paintDelegate == null) {
                assert false;
                return;
            }
        }

        canvasDelegate.getSnapshot().draw(drawable, paintDelegate, compositeOnly);
    }

    /**
     * Executes a {@link Drawable} with a given canvas. No paint object will be provided
     * to {@link GcSnapshot.Drawable#draw(Graphics2D, Paint_Delegate)}.
     * <p>Note that the drawable may actually be executed several times if there are
     * layers involved (see {@link #saveLayer(RectF, int, int)}.
     */
    private static void draw(int nCanvas, GcSnapshot.Drawable drawable) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        canvasDelegate.mSnapshot.draw(drawable);
    }

    private Canvas_Delegate(BufferedImage image) {
        mSnapshot = GcSnapshot.createDefaultSnapshot(mBufferedImage = image);
    }

    private Canvas_Delegate() {
        mSnapshot = GcSnapshot.createDefaultSnapshot(null /*image*/);
    }

    /**
     * Disposes of the {@link Graphics2D} stack.
     */
    private void dispose() {
        mSnapshot.dispose();
    }

    private int save(int saveFlags) {
        // get the current save count
        int count = mSnapshot.size();

        mSnapshot = mSnapshot.save(saveFlags);

        // return the old save count
        return count;
    }

    private int saveLayerAlpha(RectF rect, int alpha, int saveFlags) {
        Paint_Delegate paint = new Paint_Delegate();
        paint.setAlpha(alpha);
        return saveLayer(rect, paint, saveFlags);
    }

    private int saveLayer(RectF rect, Paint_Delegate paint, int saveFlags) {
        // get the current save count
        int count = mSnapshot.size();

        mSnapshot = mSnapshot.saveLayer(rect, paint, saveFlags);

        // return the old save count
        return count;
    }

    /**
     * Restores the {@link GcSnapshot} to <var>saveCount</var>
     * @param saveCount the saveCount
     */
    private void restoreTo(int saveCount) {
        mSnapshot = mSnapshot.restoreTo(saveCount);
    }

    /**
     * Restores the {@link GcSnapshot} to <var>saveCount</var>
     * @param saveCount the saveCount
     */
    private void restore() {
        mSnapshot = mSnapshot.restore();
    }

    private boolean clipRect(float left, float top, float right, float bottom, int regionOp) {
        return mSnapshot.clipRect(left, top, right, bottom, regionOp);
    }

    private void setBitmap(BufferedImage image) {
        mBufferedImage = image;
        assert mSnapshot.size() == 1;
        mSnapshot.setImage(mBufferedImage);
    }

    private static void drawBitmap(
            int nativeCanvas,
            final BufferedImage image,
            final Bitmap.Config mBitmapConfig,
            int nativePaintOrZero,
            final int sleft, final int stop, final int sright, final int sbottom,
            final int dleft, final int dtop, final int dright, final int dbottom) {
        // get the delegate from the native int.
        Canvas_Delegate canvasDelegate = sManager.getDelegate(nativeCanvas);
        if (canvasDelegate == null) {
            assert false;
            return;
        }

        // get the delegate from the native int.
        Paint_Delegate paintDelegate = null;
        if (nativePaintOrZero > 0) {
            paintDelegate = Paint_Delegate.getDelegate(nativePaintOrZero);
            if (paintDelegate == null) {
                assert false;
                return;
            }
        }

        // if the bitmap config is alpha_8, then we erase all color value from it
        // before drawing it.
        if (mBitmapConfig == Bitmap.Config.ALPHA_8) {
            int w = image.getWidth();
            int h = image.getHeight();
            int[] argb = new int[w*h];
            image.getRGB(0, 0, image.getWidth(), image.getHeight(),
                    argb, 0, image.getWidth());

            final int length = argb.length;
            for (int i = 0 ; i < length; i++) {
                argb[i] &= 0xFF000000;
            }
            image.setRGB(0, 0, w, h, argb, 0, w);
        }

        draw(nativeCanvas, nativePaintOrZero, true /*compositeOnly*/,
                new GcSnapshot.Drawable() {
                    public void draw(Graphics2D graphics, Paint_Delegate paint) {
                        if (paint != null && paint.isFilterBitmap()) {
                            graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                                    RenderingHints.VALUE_INTERPOLATION_BILINEAR);
                        }

                        //FIXME add support for canvas, screen and bitmap densities.
                        graphics.drawImage(image, dleft, dtop, dright, dbottom,
                                sleft, stop, sright, sbottom, null);
                    }
        });
    }
}