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popping characters: adjust height to size

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This commit is contained in:
hrj 2022-04-03 22:49:35 +05:30
parent bfc7174e2a
commit 7f77f819dd
1 changed files with 15 additions and 11 deletions
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26
src/main/java/lc/captchas/PoppingCharactersCaptcha.java
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@ -9,7 +9,6 @@ import java.io.IOException;
import java.util.Map; import java.util.Map;
import java.util.function.Consumer; import java.util.function.Consumer;
import java.util.stream.IntStream; import java.util.stream.IntStream;
import java.util.LinkedList;
import java.util.List; import java.util.List;
import javax.imageio.stream.MemoryCacheImageOutputStream; import javax.imageio.stream.MemoryCacheImageOutputStream;
@ -20,26 +19,26 @@ import lc.misc.HelperFunctions;
import lc.misc.GifSequenceWriter; import lc.misc.GifSequenceWriter;
public class PoppingCharactersCaptcha implements ChallengeProvider { public class PoppingCharactersCaptcha implements ChallengeProvider {
private final Font font = new Font("Arial", Font.ROMAN_BASELINE, 48);
private Integer[] computeOffsets(final int width, final int height, final String text) { private int[] computeOffsets(final Font font, final int width, final int height, final String text) {
final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
final var graphics2D = img.createGraphics(); final var graphics2D = img.createGraphics();
final var frc = graphics2D.getFontRenderContext(); final var frc = graphics2D.getFontRenderContext();
final var advances = new LinkedList<Integer>(); final var advances = new int[text.length() + 1];
final var spacing = font.getStringBounds(" ", frc).getWidth() / 3; final var spacing = font.getStringBounds(" ", frc).getWidth() / 3;
var currX = 0; var currX = 0;
for (int i = 0; i < text.length(); i++) { for (int i = 0; i < text.length(); i++) {
final var c = text.charAt(i); final var c = text.charAt(i);
advances.add(currX); advances[i] = currX;
currX += font.getStringBounds(String.valueOf(c), frc).getWidth(); currX += font.getStringBounds(String.valueOf(c), frc).getWidth();
currX += spacing; currX += spacing;
}; };
advances[text.length()] = currX;
graphics2D.dispose(); graphics2D.dispose();
return advances.toArray(new Integer[]{}); return advances;
} }
private BufferedImage makeImage(final int width, final int height, final Consumer<Graphics2D> f) { private BufferedImage makeImage(final Font font, final int width, final int height, final Consumer<Graphics2D> f) {
final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); final var img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
final var graphics2D = img.createGraphics(); final var graphics2D = img.createGraphics();
graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
@ -56,21 +55,26 @@ public class PoppingCharactersCaptcha implements ChallengeProvider {
private byte[] gifCaptcha(final int width, final int height, final String text) { private byte[] gifCaptcha(final int width, final int height, final String text) {
try { try {
final var fontHeight = (int) (height * 0.5);
final Font font = new Font("Arial", Font.ROMAN_BASELINE, fontHeight);
final var byteArrayOutputStream = new ByteArrayOutputStream(); final var byteArrayOutputStream = new ByteArrayOutputStream();
final var output = new MemoryCacheImageOutputStream(byteArrayOutputStream); final var output = new MemoryCacheImageOutputStream(byteArrayOutputStream);
final var writer = new GifSequenceWriter(output, 1, 900, true); final var writer = new GifSequenceWriter(output, 1, 900, true);
final var advances = computeOffsets(width, height, text); final var advances = computeOffsets(font, width, height, text);
final var expectedWidth = advances[advances.length - 1];
final var scale = width / (float) expectedWidth;
final var prevColor = Color.getHSBColor(0f, 0f, 0.1f); final var prevColor = Color.getHSBColor(0f, 0f, 0.1f);
IntStream.range(0, text.length()).forEach(i -> { IntStream.range(0, text.length()).forEach(i -> {
final var color = Color.getHSBColor(HelperFunctions.randomNumber(0, 100)/100.0f, 0.6f, 1.0f); final var color = Color.getHSBColor(HelperFunctions.randomNumber(0, 100)/100.0f, 0.6f, 1.0f);
final var nextImage = makeImage(width, height, (g) -> { final var nextImage = makeImage(font, width, height, (g) -> {
g.scale(scale, 1);
if (i > 0) { if (i > 0) {
final var prevI = (i - 1) % text.length(); final var prevI = (i - 1) % text.length();
g.setColor(prevColor); g.setColor(prevColor);
g.drawString(String.valueOf(text.charAt(prevI)), advances[prevI] + jitter(), 45 + jitter()); g.drawString(String.valueOf(text.charAt(prevI)), advances[prevI] + jitter(), fontHeight*1.1f + jitter());
} }
g.setColor(color); g.setColor(color);
g.drawString(String.valueOf(text.charAt(i)), advances[i] + jitter(), 45 + jitter()); g.drawString(String.valueOf(text.charAt(i)), advances[i] + jitter(), fontHeight*1.1f + jitter());
}); });
try { try {
writer.writeToSequence(nextImage); writer.writeToSequence(nextImage);