SVG.java 文件源码

/**
 * Renders this SVG document to a Picture object using the specified view defined in the document.
 * <p>
 * A View is an special element in a SVG document that describes a rectangular area in the document.
 * Calling this method with a {@code viewId} will result in the specified view being positioned and scaled
 * to the viewport.  In other words, use {@link #renderToPicture()} to render the whole document, or use this
 * method instead to render just a part of it.
 *
 * @param viewId         the id of a view element in the document that defines which section of the document is to be visible.
 * @param widthInPixels  the width of the initial viewport
 * @param heightInPixels the height of the initial viewport
 * @return a Picture object suitable for later rendering using {@code Canvas.drawPicture()}, or null if the viewId was not found.
 */
public Picture renderViewToPicture(String viewId, int widthInPixels, int heightInPixels) {
    SvgObject obj = this.getElementById(viewId);
    if (obj == null)
        return null;
    if (!(obj instanceof SVG.View))
        return null;

    SVG.View view = (SVG.View) obj;

    if (view.viewBox == null) {
        Log.w(TAG, "View element is missing a viewBox attribute.");
        return null;
    }

    Picture picture = new Picture();
    Canvas canvas = picture.beginRecording(widthInPixels, heightInPixels);
    Box viewPort = new Box(0f, 0f, (float) widthInPixels, (float) heightInPixels);

    SVGAndroidRenderer renderer = new SVGAndroidRenderer(canvas, viewPort, this.renderDPI);

    renderer.renderDocument(this, view.viewBox, view.preserveAspectRatio, false);

    picture.endRecording();
    return picture;
}