forplay.html.HtmlImageLayerDom.java Source code

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Here is the source code for forplay.html.HtmlImageLayerDom.java

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/**
 * Copyright 2010 The ForPlay Authors
 * 
 * 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 forplay.html;

import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.ImageElement;
import com.google.gwt.dom.client.Style;
import com.google.gwt.dom.client.Style.Overflow;
import com.google.gwt.dom.client.Style.Unit;

import forplay.core.Asserts;
import forplay.core.Image;
import forplay.core.ImageLayer;
import forplay.core.ResourceCallback;

class HtmlImageLayerDom extends HtmlLayerDom implements ImageLayer {

    private float width, height;
    private boolean widthSet, heightSet;
    private float sx, sy, sw, sh;
    private boolean sourceRectSet;
    private boolean repeatX, repeatY;

    private HtmlImage htmlImage;

    public HtmlImageLayerDom() {
        super(Document.get().createDivElement());

        setRepeatX(false);
        setRepeatY(false);
    }

    HtmlImageLayerDom(final Image img) {
        this();
        setImage(img);
    }

    @Override
    public void clearHeight() {
        heightSet = true;
        applySize();
    }

    @Override
    public void clearSourceRect() {
        this.sourceRectSet = false;
        applyBackgroundSize();
    }

    @Override
    public void clearWidth() {
        widthSet = true;
        applySize();
    }

    @Override
    public Image image() {
        return htmlImage;
    }

    @Override
    public void setHeight(float height) {
        Asserts.checkArgument(height > 0, "Height must be > 0");

        heightSet = true;
        this.height = height;
        applySize();
    }

    @Override
    public void setImage(final Image img) {
        Asserts.checkArgument(img instanceof HtmlImage);

        // Make sure redundant setImage() calls don't cost much.
        if (htmlImage == img) {
            return;
        }

        htmlImage = (HtmlImage) img;
        ImageElement imgElem = htmlImage.img.cast();
        element().getStyle().setBackgroundImage("url(" + imgElem.getSrc() + ")");
        element().getStyle().setOverflow(Overflow.HIDDEN);

        img.addCallback(new ResourceCallback<Image>() {
            @Override
            public void done(Image resource) {
                applySize();
                applyBackgroundSize();
            }

            @Override
            public void error(Throwable err) {
                // Nothing to be done about errors.
            }
        });
    }

    @Override
    public void setRepeatX(boolean repeat) {
        Asserts.checkArgument(!repeat || !sourceRectSet, "Cannot repeat when source rect is used");

        repeatX = repeat;
        applyBackgroundSize();
    }

    @Override
    public void setRepeatY(boolean repeat) {
        Asserts.checkArgument(!repeat || !sourceRectSet, "Cannot repeat when source rect is used");

        repeatY = repeat;
        applyBackgroundSize();
    }

    @Override
    public void setSourceRect(float sx, float sy, float sw, float sh) {
        Asserts.checkState(!repeatX && !repeatY, "Cannot use source rect when repeating x or y");
        Asserts.checkArgument(sw != 0 && sh != 0); // Will cause div-by-zero

        // Early out if there's no change. applyBackgroundSize() isn't free.
        if (sourceRectSet && (this.sx == sx) && (this.sy == sy) && (this.sw == sw) && (this.sh == sh)) {
            return;
        }

        this.sourceRectSet = true;
        this.sx = sx;
        this.sy = sy;
        this.sw = sw;
        this.sh = sh;
        applyBackgroundSize();
    }

    @Override
    public void setWidth(float width) {
        Asserts.checkArgument(width > 0, "Width must be > 0");

        widthSet = true;
        this.width = width;
        applySize();
    }

    @Override
    public void setSize(float width, float height) {
        Asserts.checkArgument(width > 0 && height > 0, "Width and height must be > 0 (got %dx%d)", width, height);

        widthSet = true;
        this.width = width;
        heightSet = true;
        this.height = height;
        applySize();
    }

    private void applyBackgroundSize() {
        Style style = element().getStyle();

        // Set background-repeat to get the right repeating behavior.
        String repeat = repeatX ? "repeat-x " : "";
        repeat += repeatY ? "repeat-y" : "";
        style.setProperty("backgroundRepeat", repeat);

        // Set background-size to get the right pinning behavior.
        if (sourceRectSet) {
            float wratio = widthSet ? (width / sw) : (image().width() / sw);
            float hratio = heightSet ? (height / sh) : (image().height() / sh);
            if (wratio == 0) {
                wratio = 1;
            }
            if (hratio == 0) {
                hratio = 1;
            }
            float backWidth = image().width() * wratio;
            float backHeight = image().height() * hratio;

            style.setProperty("backgroundSize", backWidth + "px " + backHeight + "px");
            style.setProperty("backgroundPosition", (-sx * wratio) + "px " + (-sy * hratio) + "px");
        } else {
            String size = repeatX ? image().width() + "px " : "100% ";
            size += repeatY ? image().height() + "px" : "100%";
            style.setProperty("backgroundSize", size);
            style.clearProperty("backgroundPosition");
        }
    }

    private void applySize() {
        Style style = element().getStyle();
        style.setWidth(widthSet ? width : htmlImage.img.getWidth(), Unit.PX);
        style.setHeight(heightSet ? height : htmlImage.img.getHeight(), Unit.PX);
        if (sourceRectSet) {
            applyBackgroundSize();
        }
    }
}