design/designer-base/src/main/java/com/fr/base/svg/SVGTranscoder.java

package com.fr.base.svg;

import com.fr.stable.AssistUtils;
import com.fr.value.AtomicNotNullLazyValue;
import org.apache.batik.anim.dom.SAXSVGDocumentFactory;
import org.apache.batik.anim.dom.SVGOMDocument;
import org.apache.batik.bridge.BridgeContext;
import org.apache.batik.bridge.UserAgent;
import org.apache.batik.transcoder.SVGAbstractTranscoder;
import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderInput;
import org.apache.batik.transcoder.TranscoderOutput;
import org.apache.batik.transcoder.image.ImageTranscoder;
import org.apache.batik.util.XMLResourceDescriptor;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.w3c.dom.Element;
import org.w3c.dom.svg.SVGDocument;

import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.StringReader;

/**
 * 可以根据某个缩放倍数scale，将SVG图片转化为Image对象
 * @author Yvan
 * @version 10.0
 * Created by Yvan on 2020/12/17
 */
public class SVGTranscoder extends ImageTranscoder {

    private static final float DEFAULT_VALUE = -1.0F;
    public static final float ICON_DEFAULT_SIZE = 16F;
    private float origDocWidth;
    private float origDocHeight;
    @Nullable
    private BufferedImage image;
    private final double scale;

    @NotNull
    private static AtomicNotNullLazyValue<Double> iconMaxSize = new AtomicNotNullLazyValue<Double>() {
        @NotNull
        @Override
        protected Double compute() {
            double maxSize = Double.MAX_VALUE;
            if (!GraphicsEnvironment.isHeadless()) {
                GraphicsDevice defaultScreenDevice = GraphicsEnvironment
                        .getLocalGraphicsEnvironment()
                        .getDefaultScreenDevice();
                Rectangle bounds = defaultScreenDevice.getDefaultConfiguration().getBounds();
                AffineTransform tx = defaultScreenDevice
                        .getDefaultConfiguration()
                        .getDefaultTransform();
                maxSize = Math.max(bounds.width * tx.getScaleX(), bounds.height * tx.getScaleY());
            }
            return maxSize;
        }
    };

    public SVGTranscoder(double scale) {
        this.scale = scale;
        this.width = ICON_DEFAULT_SIZE;
        this.height = ICON_DEFAULT_SIZE;
    }

    public SVGTranscoder(double scale, float width, float height) {
        this.scale = scale;
        this.width = width;
        this.height = height;
    }

    public final float getOrigDocWidth() {
        return this.origDocWidth;
    }

    public final void setOrigDocWidth(float origDocWidth) {
        this.origDocWidth = origDocWidth;
    }

    public final float getOrigDocHeight() {
        return this.origDocHeight;
    }

    public final void setOrigDocHeight(float origDocHeight) {
        this.origDocHeight = origDocHeight;
    }

    public static double getIconMaxSize() {
        return iconMaxSize.getValue();
    }

    @Nullable
    public final BufferedImage getImage() {
        return this.image;
    }

    @NotNull
    public static SVGTranscoder createImage(double scale, @NotNull TranscoderInput input) throws TranscoderException {
        return createImage(scale, input, -1, -1);
    }

    @NotNull
    public static SVGTranscoder createImage(double scale, @NotNull TranscoderInput input, float overriddenWidth, float overriddenHeight) throws TranscoderException {
        return createImage(scale, input, overriddenWidth, overriddenHeight, ICON_DEFAULT_SIZE, ICON_DEFAULT_SIZE);
    }

    @NotNull
    public static SVGTranscoder createImage(double scale, @NotNull TranscoderInput input, float overriddenWidth, float overriddenHeight, float width, float height) throws TranscoderException {
        SVGTranscoder transcoder = new SVGTranscoder(scale, width, height);
        if (!AssistUtils.equals(overriddenWidth, DEFAULT_VALUE)) {
            transcoder.addTranscodingHint(SVGAbstractTranscoder.KEY_WIDTH, overriddenWidth);
        }

        if (!AssistUtils.equals(overriddenHeight, DEFAULT_VALUE)) {
            transcoder.addTranscodingHint(SVGAbstractTranscoder.KEY_HEIGHT, overriddenHeight);
        }

        double iconMaxSize = SVGTranscoder.iconMaxSize.getValue();
        transcoder.addTranscodingHint(SVGAbstractTranscoder.KEY_MAX_WIDTH, (float) iconMaxSize);
        transcoder.addTranscodingHint(SVGAbstractTranscoder.KEY_MAX_HEIGHT, (float) iconMaxSize);
        transcoder.transcode(input, null);
        return transcoder;
    }

    private static SVGDocument createFallbackPlaceholder() {
        try {
            String fallbackIcon = "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"16\" height=\"16\" viewBox=\"0 0 16 16\">\n" +
                    "  <rect x=\"1\" y=\"1\" width=\"14\" height=\"14\" fill=\"none\" stroke=\"red\" stroke-width=\"2\"/>\n" +
                    "  <line x1=\"1\" y1=\"1\" x2=\"15\" y2=\"15\" stroke=\"red\" stroke-width=\"2\"/>\n" +
                    "  <line x1=\"1\" y1=\"15\" x2=\"15\" y2=\"1\" stroke=\"red\" stroke-width=\"2\"/>\n" +
                    "</svg>\n";

            SAXSVGDocumentFactory factory = new SAXSVGDocumentFactory(XMLResourceDescriptor.getXMLParserClassName());
            return (SVGDocument) factory.createDocument(null, new StringReader(fallbackIcon));
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

    @Override
    protected void setImageSize(float docWidth, float docHeight) {
        super.setImageSize((float) (docWidth * this.scale), (float) (docHeight * this.scale));
        this.origDocWidth = docWidth;
        this.origDocHeight = docHeight;
    }

    @Override
    @NotNull
    public BufferedImage createImage(int width, int height) {
        return new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    }

    @Override
    public void writeImage(@NotNull BufferedImage image, @Nullable TranscoderOutput output) {
        this.image = image;
    }

    @Override
    @NotNull
    protected UserAgent createUserAgent() {
        return new SVGAbstractTranscoderUserAgent() {
            @Override
            @NotNull
            public SVGDocument getBrokenLinkDocument(@NotNull Element e, @NotNull String url, @NotNull String message) {
                return createFallbackPlaceholder();
            }
        };
    }

    /**
     * 开放访问权限
     */
    @Override
    public BridgeContext createBridgeContext(SVGOMDocument doc) {
        return super.createBridgeContext(doc);
    }
}