Added a QRCodeRenderer to make rendering QRCodes reusable out of the box. This creates a much more usable experience without needing to read and understand lower level details about graphics, QRCode, etc.pull/205/head
Charlie Hubbard
1 year ago
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GitHub
parent
42a886d784
commit
d410c550f8
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package com.fuseanalytics.archiver.util;
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import io.nayuki.qrcodegen.QrCode;
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import javax.imageio.ImageIO;
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import java.awt.*;
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import java.awt.image.BufferedImage;
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import java.io.File;
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import java.io.IOException;
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import java.io.OutputStream;
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/**
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* Use this class to generate images of your {@link io.nayuki.qrcodegen.QrCode} instances.
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* It uses sensible defaults to make the resulting QRCode look presentable without much
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* tweaking. This class can be used by multiple threads provided after construction and
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* configuration. So any render* method will not cause threading issues, but calling the
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* configuration methods {@link #colors(Color, Color)}, {@link #border(int)}, {@link #scale}
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* will cause unpredictable errors. As long as you use the configuration methods on one
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* thread before sharing the instance and only use render* methods from multiple threads
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* this class is thread safe.
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* <p>
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* Here is a simple example of generating a {@see java.awt.BufferedImage}:
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* </p>
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*
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* <pre>{@code
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* QrCode qr = QrCode.encodeText( "Hello World!", QrCode.Ecc.MEDIUM );
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* BufferedImage img = new QrCodeRenderer().renderImage(qrCode);
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* }</pre>
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*
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* <p>
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* Here is an example, for rendering a PNG to a file:
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* </p>
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* <pre>{@code
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* QrCode qr = QrCode.encodeText( "Hello World!", QrCode.Ecc.MEDIUM );
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* File target = new QrCodeRenderer().renderFile(qrCode, "png", new File("output.png"));
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* }</pre>
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*
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* <p>
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* Here's an example of tweaking the defaults and rendering a PNG to an OutputStream:
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* </p>
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* <pre>{@code
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* QrCode qr = QrCode.encodeText( "Hello World!", QrCode.Ecc.MEDIUM );
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* ByteArrayOutputStream baos = new ByteArrayOutputStream();
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* File target = new QrCodeRenderer()
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* .scale(4)
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* .border(10)
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* .colors(Color.BLUE, Color.WHITE)
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* .renderStream(qrCode, "png", baos);
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* }</pre>
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*
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* <p>
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* Here's an example, for rendering to SVG:
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* </p>
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* <pre>{@code
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* QrCode qr = QrCode.encodeText( "Hello World!", QrCode.Ecc.MEDIUM );
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* String svg = new QrCodeRenderer().renderSvg(qrCode);
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* }</pre>
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*/
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public class QrCodeRenderer {
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/**
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* The scale to use when rendering bitmap based images. Default is 5.
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*/
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private int scale = 5;
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/**
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* The size of border in pixels. THe border will be scaled by the scale factor.
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* This provides some whitespace around QR code. This area will be rendered using
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* the light color. Default is 2.
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*/
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private int border = 2;
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/**
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* This the dark color used to render the QR code. The default is black.
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*/
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private Color darkColor = Color.BLACK;
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/**
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* This is the light color used to render the background of the QR Code.
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*/
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private Color lightColor = Color.WHITE;
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/**
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* Renders a BufferedImage of the given QRCode object.
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* @param qrCode the QR code to use to render into a BufferedImage.
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* @return The bitmap rendering of the given QR Code.
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*/
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public BufferedImage renderImage(QrCode qrCode) {
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BufferedImage img = new BufferedImage((qrCode.size + border * 2) * scale, (qrCode.size + border * 2) * scale, BufferedImage.TYPE_INT_RGB);
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for( int y = 0; y < img.getHeight(); y++ ) {
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for( int x = 0; x < img.getWidth(); x++ ) {
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int sx = x / scale - border;
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int sy = y / scale - border;
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boolean color = qrCode.getModule(sx,sy);
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img.setRGB(x, y, color ? darkColor.getRGB() : lightColor.getRGB() );
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}
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}
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return img;
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}
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/**
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* Renders an SVG document of the given QR Code.
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* @param qrCode the QRCode to render into the SVG document.
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* @return a String that contains the SVG markup of the QR Code.
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*/
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public String renderSvg(QrCode qrCode) {
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long brd = border;
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StringBuilder buffer = new StringBuilder()
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.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n")
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.append("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n")
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.append(String.format("<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 %1$d %1$d\" stroke=\"none\">\n",
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qrCode.size + brd * 2))
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.append("\t<rect width=\"100%\" height=\"100%\" fill=\"").append(toRgb(lightColor)).append("\"/>\n")
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.append("\t<path d=\"");
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for (int y = 0; y < qrCode.size; y++) {
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for (int x = 0; x < qrCode.size; x++) {
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if (qrCode.getModule(x, y)) {
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if (x != 0 || y != 0)
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buffer.append(" ");
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buffer.append(String.format("M%d,%dh1v1h-1z", x + brd, y + brd));
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}
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}
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}
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return buffer
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.append("\" fill=\"").append(toRgb(darkColor)).append("\"/>\n")
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.append("</svg>\n")
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.toString();
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}
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/**
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* Renders the QR Code to a bitmap and writes that to the given file in the given format provided.
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* @param qrCode The QRCode to generate the bitmap of.
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* @param formatName The image format to write (png, jpeg, etc). These are the same formats supported by {@see javax.imageio.ImageIO}.
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* @param output A java.io.File you want to write the given QRCode in the given format into.
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* @return Returns the given File for convenience that contains the bitmap of the QRCode.
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* @throws IOException if any IOException happens while writing to the given File.
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* @throws IllegalArgumentException if the given formatName cannot be found in ImageIO library.
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*/
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public File renderFile(QrCode qrCode, String formatName, File output) throws IOException {
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BufferedImage img = renderImage(qrCode);
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if( ImageIO.write( img, formatName, output ) ) {
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return output;
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} else {
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throw new IllegalArgumentException("No appropriate writer found for formatName=" + formatName );
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}
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}
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/**
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* Renders the QR Code to a bitmap and writes that to the given OutputStream in the given format provided.
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* @param qrCode The QRCode to generate the bitmap of.
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* @param formatName The image format to write (png, jpeg, etc). These are the same formats supported by {@see javax.imageio.ImageIO}.
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* @param stream The OutputStream in which to write the bitmap image of the given QRCode in the given formatName into.
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* @throws IOException if any IOException happens while writing to the given OutputStream.
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* @throws IllegalArgumentException if the given formatName cannot be found in ImageIO library.
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*/
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public void renderStream(QrCode qrCode, String formatName, OutputStream stream ) throws IOException {
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BufferedImage img = renderImage( qrCode );
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if( !ImageIO.write( img, formatName, stream ) ) {
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throw new IllegalArgumentException("No appropriate writer found for formatName=" + formatName );
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}
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}
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private String toRgb(Color color) {
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return "rgb(" + color.getRed() + " " + color.getGreen() + " " + color.getBlue() + ")";
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}
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/**
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* Overwrite the border default by specifying the number of pixels to use as a border. This is
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* the number of pixels to use before scaling is applied so the resulting border will be scaled
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* up if scale > 1.
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* @param border pixels to add around the resulting QRCode bitmap
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* @return this
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*/
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public QrCodeRenderer border( int border ) {
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if( border < 0 ) throw new IllegalArgumentException("Border must be non-negative: " + border );
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if( border > Integer.MAX_VALUE / 2 ) throw new IllegalArgumentException("Border size is too large.");
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this.border = border;
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return this;
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}
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/**
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* Sets the scale to use when writing into the Bitmap image.
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*
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* @param scale the amount to scale the image by. 1 performs no sale, 2 doubles it, 3 triples, etc.
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* @return this
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*/
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public QrCodeRenderer scale( int scale ) {
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if( scale < 0 ) throw new IllegalArgumentException("Scale must be non-negative: " + scale );
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if( (QrCode.MAX_VERSION * 4 + 17) * scale + border*2 > Integer.MAX_VALUE / scale ) throw new IllegalArgumentException("Scale is too large: " + scale);
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this.scale = scale;
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return this;
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}
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/**
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* Sets the colors to use when rendering the QRCode. The dark color will be used to write
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* the QR Code, and the light color will be used as the background.
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* @param darkColor the color to use for the QRCode
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* @param lightColor the color to use as the background color.
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* @return this
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*/
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public QrCodeRenderer colors( Color darkColor, Color lightColor ) {
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this.darkColor = darkColor;
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this.lightColor = lightColor;
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return this;
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}
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}
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