openharmony/third_party_qrcodegen
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Moved QrCode.toImage() out of the library and into the runnable demo program, slightly adapted some code, updated documentation comments.

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Project Nayuki 2021-07-28 19:00:32 +00:00
parent e476134828
commit 2515a4213c
4 changed files with 53 additions and 50 deletions
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4
Readme.markdown
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@ -18,7 +18,7 @@ Features
Core features:
* Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard
* Output formats: Raw modules/pixels of the QR symbol, SVG XML string, `BufferedImage` raster bitmap
* Output formats: Raw modules/pixels of the QR symbol, SVG XML string
* Encodes numeric and special-alphanumeric text in less space than general text
* Encodes Japanese Unicode text in kanji mode to save a lot of space compared to UTF-8 bytes
* Computes optimal segment mode switching for text with mixed numeric/alphanumeric/general/kanji parts
@ -44,7 +44,7 @@ Examples
// Simple operation
QrCode qr0 = QrCode.encodeText("Hello, world!", QrCode.Ecc.MEDIUM);
BufferedImage img = qr0.toImage(4, 10);
BufferedImage img = toImage(qr0, 4, 10); // See QrCodeGeneratorDemo
ImageIO.write(img, "png", new File("qr-code.png"));
// Manual operation

29
src/io/nayuki/fastqrcodegen/QrCode.java
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@ -23,7 +23,6 @@
package io.nayuki.fastqrcodegen;
import java.awt.image.BufferedImage;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
@ -278,34 +277,6 @@ public final class QrCode {
}
/**
* Returns a raster image depicting this QR Code, with the specified module scale and border modules.
* <p>For example, toImage(scale=10, border=4) means to pad the QR Code with 4 light
* border modules on all four sides, and use 10&#xD7;10 pixels to represent each module.
* The resulting image only contains the hex colors 000000 and FFFFFF.
* @param scale the side length (measured in pixels, must be positive) of each module
* @param border the number of border modules to add, which must be non-negative
* @return a new image representing this QR Code, with padding and scaling
* @throws IllegalArgumentException if the scale or border is out of range, or if
* {scale, border, size} cause the image dimensions to exceed Integer.MAX_VALUE
*/
public BufferedImage toImage(int scale, int border) {
if (scale <= 0 || border < 0)
throw new IllegalArgumentException("Value out of range");
if (border > Integer.MAX_VALUE / 2 || size + border * 2L > Integer.MAX_VALUE / scale)
throw new IllegalArgumentException("Scale or border too large");
BufferedImage result = new BufferedImage((size + border * 2) * scale, (size + border * 2) * scale, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < result.getHeight(); y++) {
for (int x = 0; x < result.getWidth(); x++) {
boolean color = getModule(x / scale - border, y / scale - border);
result.setRGB(x, y, color ? 0x000000 : 0xFFFFFF);
}
}
return result;
}
/**
* Returns a string of SVG code for an image depicting this QR Code, with the specified number
* of border modules. The string always uses Unix newlines (\n), regardless of the platform.

66
src/io/nayuki/fastqrcodegen/QrCodeGeneratorDemo.java
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@ -33,6 +33,7 @@ import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import javax.imageio.ImageIO;
@ -57,7 +58,7 @@ public final class QrCodeGeneratorDemo {
QrCode qr = QrCode.encodeText(text, errCorLvl); // Make the QR Code symbol
BufferedImage img = qr.toImage(10, 4); // Convert to bitmap image
BufferedImage img = toImage(qr, 10, 4); // Convert to bitmap image
File imgFile = new File("hello-world-QR.png"); // File path for output
ImageIO.write(img, "png", imgFile); // Write image to file
@ -74,15 +75,15 @@ public final class QrCodeGeneratorDemo {
// Numeric mode encoding (3.33 bits per digit)
qr = QrCode.encodeText("314159265358979323846264338327950288419716939937510", QrCode.Ecc.MEDIUM);
writePng(qr.toImage(13, 1), "pi-digits-QR.png");
writePng(toImage(qr, 13, 1), "pi-digits-QR.png");
// Alphanumeric mode encoding (5.5 bits per character)
qr = QrCode.encodeText("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCode.Ecc.HIGH);
writePng(qr.toImage(10, 2), "alphanumeric-QR.png");
writePng(toImage(qr, 10, 2), "alphanumeric-QR.png");
// Unicode text as UTF-8
qr = QrCode.encodeText("こんにちwa、世界！ αβγδ", QrCode.Ecc.QUARTILE);
writePng(qr.toImage(10, 3), "unicode-QR.png");
writePng(toImage(qr, 10, 3), "unicode-QR.png");
// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
qr = QrCode.encodeText(
@ -93,7 +94,7 @@ public final class QrCodeGeneratorDemo {
+ "for the hot day made her feel very sleepy and stupid), whether the pleasure of making a "
+ "daisy-chain would be worth the trouble of getting up and picking the daisies, when suddenly "
+ "a White Rabbit with pink eyes ran close by her.", QrCode.Ecc.HIGH);
writePng(qr.toImage(6, 10), "alice-wonderland-QR.png");
writePng(toImage(qr, 6, 10), "alice-wonderland-QR.png");
}
@ -106,32 +107,32 @@ public final class QrCodeGeneratorDemo {
String silver0 = "THE SQUARE ROOT OF 2 IS 1.";
String silver1 = "41421356237309504880168872420969807856967187537694807317667973799";
qr = QrCode.encodeText(silver0 + silver1, QrCode.Ecc.LOW);
writePng(qr.toImage(10, 3), "sqrt2-monolithic-QR.png");
writePng(toImage(qr, 10, 3), "sqrt2-monolithic-QR.png");
segs = Arrays.asList(
QrSegment.makeAlphanumeric(silver0),
QrSegment.makeNumeric(silver1));
qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
writePng(qr.toImage(10, 3), "sqrt2-segmented-QR.png");
writePng(toImage(qr, 10, 3), "sqrt2-segmented-QR.png");
// Illustration "golden"
String golden0 = "Golden ratio φ = 1.";
String golden1 = "6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911374";
String golden2 = "......";
qr = QrCode.encodeText(golden0 + golden1 + golden2, QrCode.Ecc.LOW);
writePng(qr.toImage(8, 5), "phi-monolithic-QR.png");
writePng(toImage(qr, 8, 5), "phi-monolithic-QR.png");
segs = Arrays.asList(
QrSegment.makeBytes(golden0.getBytes(StandardCharsets.UTF_8)),
QrSegment.makeNumeric(golden1),
QrSegment.makeAlphanumeric(golden2));
qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
writePng(qr.toImage(8, 5), "phi-segmented-QR.png");
writePng(toImage(qr, 8, 5), "phi-segmented-QR.png");
// Illustration "Madoka": kanji, kana, Cyrillic, full-width Latin, Greek characters
String madoka = "「魔法少女まどか☆マギカ」って、　ИАИ　ｄｅｓｕ　κα？";
qr = QrCode.encodeText(madoka, QrCode.Ecc.LOW);
writePng(qr.toImage(9, 4), "madoka-utf8-QR.png");
writePng(toImage(qr, 9, 4), "madoka-utf8-QR.png");
int[] kanjiChars = { // Kanji mode encoding (13 bits per character)
0x0035, 0x1002, 0x0FC0, 0x0AED, 0x0AD7,
@ -146,7 +147,7 @@ public final class QrCodeGeneratorDemo {
bb.appendBits(c, 13);
segs = Arrays.asList(new QrSegment(QrSegment.Mode.KANJI, kanjiChars.length, bb.data, bb.bitLength));
qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
writePng(qr.toImage(9, 4), "madoka-kanji-QR.png");
writePng(toImage(qr, 9, 4), "madoka-kanji-QR.png");
}
@ -158,26 +159,57 @@ public final class QrCodeGeneratorDemo {
// Project Nayuki URL
segs = QrSegment.makeSegments("https://www.nayuki.io/");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, QrCode.MIN_VERSION, QrCode.MAX_VERSION, -1, true); // Automatic mask
writePng(qr.toImage(8, 6), "project-nayuki-automask-QR.png");
writePng(toImage(qr, 8, 6), "project-nayuki-automask-QR.png");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, QrCode.MIN_VERSION, QrCode.MAX_VERSION, 3, true); // Force mask 3
writePng(qr.toImage(8, 6), "project-nayuki-mask3-QR.png");
writePng(toImage(qr, 8, 6), "project-nayuki-mask3-QR.png");
// Chinese text as UTF-8
segs = QrSegment.makeSegments("維基百科（Wikipedia，聆聽i/ˌwɪkᵻˈpiːdi.ə/）是一個自由內容、公開編輯且多語言的網路百科全書協作計畫");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, QrCode.MIN_VERSION, QrCode.MAX_VERSION, 0, true); // Force mask 0
writePng(qr.toImage(10, 3), "unicode-mask0-QR.png");
writePng(toImage(qr, 10, 3), "unicode-mask0-QR.png");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, QrCode.MIN_VERSION, QrCode.MAX_VERSION, 1, true); // Force mask 1
writePng(qr.toImage(10, 3), "unicode-mask1-QR.png");
writePng(toImage(qr, 10, 3), "unicode-mask1-QR.png");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, QrCode.MIN_VERSION, QrCode.MAX_VERSION, 5, true); // Force mask 5
writePng(qr.toImage(10, 3), "unicode-mask5-QR.png");
writePng(toImage(qr, 10, 3), "unicode-mask5-QR.png");
qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, QrCode.MIN_VERSION, QrCode.MAX_VERSION, 7, true); // Force mask 7
writePng(qr.toImage(10, 3), "unicode-mask7-QR.png");
writePng(toImage(qr, 10, 3), "unicode-mask7-QR.png");
}
/*---- Utilities ----*/
/**
* Returns a raster image depicting the specified QR Code, with the specified module scale and border modules.
* <p>For example, toImage(qr, scale=10, border=4) means to pad the QR Code with 4 light
* border modules on all four sides, and use 10&#xD7;10 pixels to represent each module.
* The resulting image only contains the hex colors 000000 and FFFFFF.
* @param qr the QR Code to render (not {@code null})
* @param scale the side length (measured in pixels, must be positive) of each module
* @param border the number of border modules to add, which must be non-negative
* @return a new image representing the QR Code, with padding and scaling
* @throws NullPointerException if the QR Code is {@code null}
* @throws IllegalArgumentException if the scale or border is out of range, or if
* {scale, border, size} cause the image dimensions to exceed Integer.MAX_VALUE
*/
private static BufferedImage toImage(QrCode qr, int scale, int border) {
Objects.requireNonNull(qr);
if (scale <= 0 || border < 0)
throw new IllegalArgumentException("Value out of range");
if (border > Integer.MAX_VALUE / 2 || qr.size + border * 2L > Integer.MAX_VALUE / scale)
throw new IllegalArgumentException("Scale or border too large");
BufferedImage result = new BufferedImage((qr.size + border * 2) * scale, (qr.size + border * 2) * scale, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < result.getHeight(); y++) {
for (int x = 0; x < result.getWidth(); x++) {
boolean color = qr.getModule(x / scale - border, y / scale - border);
result.setRGB(x, y, color ? 0x000000 : 0xFFFFFF);
}
}
return result;
}
// Helper function to reduce code duplication.
private static void writePng(BufferedImage img, String filepath) throws IOException {
ImageIO.write(img, "png", new File(filepath));

4
src/io/nayuki/fastqrcodegen/package-info.java
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@ -9,7 +9,7 @@
* <p>Core features:</p>
* <ul>
* <li><p>Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard</p></li>
* <li><p>Output formats: Raw modules/pixels of the QR symbol, SVG XML string, {@code BufferedImage} raster bitmap</p></li>
* <li><p>Output formats: Raw modules/pixels of the QR symbol, SVG XML string</p></li>
* <li><p>Encodes numeric and special-alphanumeric text in less space than general text</p></li>
* <li><p>Encodes Japanese Unicode text in kanji mode to save a lot of space compared to UTF-8 bytes</p></li>
* <li><p>Computes optimal segment mode switching for text with mixed numeric/alphanumeric/general/kanji parts</p></li>
@ -32,7 +32,7 @@
*import io.nayuki.fastqrcodegen.*;
*
*QrCode qr = QrCode.encodeText("Hello, world!", QrCode.Ecc.MEDIUM);
*BufferedImage img = qr.toImage(4, 10);
*BufferedImage img = toImage(qr, 4, 10); // See QrCodeGeneratorDemo
*ImageIO.write(img, "png", new File("qr-code.png"));</pre>
* <p>Manual operation:</p>
* <pre style="margin-left:2em">import java.util.List;