Example usage for com.google.gwt.canvas.dom.client Context2d clip

Introduction

In this page you can find the example usage for com.google.gwt.canvas.dom.client Context2d clip.

Prototype

public final native void clip() ;

Source Link

Document

Creates a new clipping region from the current path.

Usage

From source file:com.sencha.gxt.chart.client.draw.engine.Canvas2d.java

License:sencha.com license

/**
 * In the Canvas2d class, this method does more or less what renderSprite does in SVG and VML - it
 * actually renders the sprite to the dom.
 * @param sprite the sprite to draw/*from w ww  .  java 2  s. c  o m*/
 */
protected void append(Sprite sprite) {
    if (sprite.isHidden() || sprite.getOpacity() == 0) {
        return;
    }
    Context2d ctx = getContext();
    ctx.save();
    //set global stuff, fill, stroke, clip, etc

    //clip - deal with translation or normal rectangle
    if (sprite.getClipRectangle() != null) {
        PreciseRectangle clip = sprite.getClipRectangle();
        if (sprite.getScaling() != null || sprite.getTranslation() != null || sprite.getRotation() != null) {
            PathSprite transPath = new PathSprite(new RectangleSprite(clip));
            transPath = transPath.map(sprite.transformMatrix());
            appendPath(ctx, transPath);
        } else {
            ctx.beginPath();
            ctx.rect(clip.getX(), clip.getY(), clip.getWidth(), clip.getHeight());
            ctx.closePath();
        }
        ctx.clip();
    }

    if (sprite.getScaling() != null || sprite.getTranslation() != null || sprite.getRotation() != null
            || (component.isViewBox() && viewbox != null)) {
        Matrix matrix = sprite.transformMatrix();
        if (matrix != null) {
            //TODO consider replacing this transform call with three distinct calls to translate/scale/rotate if cheaper
            ctx.transform(matrix.get(0, 0), matrix.get(1, 0), matrix.get(0, 1), matrix.get(1, 1),
                    matrix.get(0, 2), matrix.get(1, 2));
        }
        if (component.isViewBox() && viewbox != null) {
            double size = Math.min(getWidth() / viewbox.getWidth(), getHeight() / viewbox.getHeight());

            ctx.scale(size, size);
            ctx.translate(-viewbox.getX(), -viewbox.getY());
        }
    }

    //TODO see about caching colors via the dirty flag? If we don't use a color/gradient for a pass or three, dump it
    double opacity = Double.isNaN(sprite.getOpacity()) ? 1.0 : sprite.getOpacity();
    PreciseRectangle untransformedBbox = sprite.getPathSprite().dimensions();
    if (sprite.getStroke() != null && sprite.getStroke() != Color.NONE && sprite.getStrokeWidth() != 0) {
        ctx.setLineWidth(Double.isNaN(sprite.getStrokeWidth()) ? 1.0 : sprite.getStrokeWidth());
        ctx.setStrokeStyle(getColor(sprite.getStroke(), untransformedBbox));//TODO read bbox from cache
    }
    if (sprite.getFill() != null && sprite.getFill() != Color.NONE) {
        ctx.setFillStyle(getColor(sprite.getFill(), untransformedBbox));//TODO read bbox from cache
    }

    if (sprite instanceof PathSprite) {
        appendPath(ctx, (PathSprite) sprite);
    } else if (sprite instanceof TextSprite) {
        TextSprite text = (TextSprite) sprite;
        //TODO style and weight
        ctx.setFont(text.getFontSize() + "px " + text.getFont());
        ctx.setTextAlign(getTextAlign(text.getTextAnchor()));
        ctx.setTextBaseline(getTextBaseline(text.getTextBaseline()));
        ctx.fillText(text.getText(), text.getX(), text.getY());
    } else if (sprite instanceof RectangleSprite) {
        RectangleSprite rect = (RectangleSprite) sprite;
        if (Double.isNaN(rect.getRadius()) || rect.getRadius() == 0) {
            if (sprite.getFill() != null && sprite.getFill() != Color.NONE) {
                ctx.setGlobalAlpha(
                        Double.isNaN(sprite.getFillOpacity()) ? opacity : opacity * sprite.getFillOpacity());
                ctx.fillRect(rect.getX(), rect.getY(), rect.getWidth(), rect.getHeight());
            }
            if (sprite.getStroke() != null && sprite.getStroke() != Color.NONE
                    && sprite.getStrokeWidth() != 0) {
                ctx.setGlobalAlpha(Double.isNaN(sprite.getStrokeOpacity()) ? opacity
                        : opacity * sprite.getStrokeOpacity());
                ctx.strokeRect(rect.getX(), rect.getY(), rect.getWidth(), rect.getHeight());
            }
        } else {
            appendPath(ctx, rect.getPathSprite());
        }
    } else if (sprite instanceof CircleSprite) {
        CircleSprite circle = (CircleSprite) sprite;
        ctx.beginPath();
        ctx.arc(circle.getCenterX(), circle.getCenterY(), circle.getRadius(), 0, 2 * Math.PI);
        ctx.closePath();
        if (sprite.getFill() != null && sprite.getFill() != Color.NONE) {
            ctx.setGlobalAlpha(
                    Double.isNaN(sprite.getFillOpacity()) ? opacity : opacity * sprite.getFillOpacity());
            ctx.fill();
        }
        if (sprite.getStroke() != null && sprite.getStroke() != Color.NONE && sprite.getStrokeWidth() != 0) {
            ctx.setGlobalAlpha(
                    Double.isNaN(sprite.getStrokeOpacity()) ? opacity : opacity * sprite.getStrokeOpacity());
            ctx.stroke();
        }
    } else if (sprite instanceof EllipseSprite) {
        appendPath(ctx, sprite.getPathSprite());
    } else if (sprite instanceof ImageSprite) {
        ImageSprite image = (ImageSprite) sprite;
        ImageElement elt = Document.get().createImageElement();
        elt.setSrc(image.getResource().getSafeUri().asString());
        ctx.drawImage(elt, image.getX(), image.getY(), image.getWidth(), image.getHeight());
    }

    ctx.restore();

    if (!REDRAW_ALL) {
        renderedBbox.put(sprite, getBBox(sprite));
    }

    sprite.clearDirtyFlags();
}

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From source file:examples.geometry.demos.RegionClippingExample.java

License:Open Source License

@Override
protected ControllableShape[] createShapes(Canvas canvas, EventBus eventBus) {
    return new ControllableShape[] { new ControllableShape(canvas, eventBus) {
        {/*from   w w  w  .  j  a  v  a  2 s  .  c o m*/
            addControlPoints(new Point(100, 100), new Point(200, 200));
            addControlPoints(new Point(150, 150), new Point(250, 250));
        }

        @Override
        public Region getShape() {
            Point[] cp = getPoints();
            Region region = new Region(new Rectangle(cp[0], cp[1]), new Rectangle(cp[2], cp[3]));
            return region;
        }

        @Override
        public void onDraw(Canvas canvas) {
            Context2d context = canvas.getContext2d();
            Region region = getShape();

            context.save();
            context.beginPath();
            Rectangle rr = region.getBounds();
            context.rect(rr.getX(), rr.getY(), rr.getWidth(), rr.getHeight());
            //            context.fill();
            context.clip();

            for (int y = 0; y < 800; y += 20) {
                context.fillText(
                        "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz",
                        20, y);
            }

            context.restore();

            context.setFillStyle("blue");
            context.setGlobalAlpha(0.5);
            context.beginPath();
            for (Rectangle r : region.getShapes()) {
                context.fillRect(r.getX(), r.getY(), r.getWidth(), r.getHeight());
            }
            context.closePath();
            context.setFillStyle("black");
            context.setGlobalAlpha(1);
        }
    } };
}

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