sdk-common/src/test/java/com/android/ide/common/util/GeneratorTest.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.ide.common.util;

import junit.framework.TestCase;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/**
 * Shared test infrastructure for asset (either bitmap or vector) generator.
 */
public abstract class GeneratorTest extends TestCase {
  protected abstract String getTestDataRelPath();

  protected String generateGoldenImage(File targetDir,
                                       BufferedImage goldenImage,
                                       String missingFilePath,
                                       String filePath) throws IOException {
    if (targetDir == null) {
      fail(
        "Did not find " + missingFilePath + ". Set $ANDROID_SRC to have it created automatically");
    }
    File fileName = new File(targetDir, filePath);
    assertFalse(fileName.exists());
    if (!fileName.getParentFile().exists()) {
      boolean mkdir = fileName.getParentFile().mkdirs();
      assertTrue(fileName.getParent(), mkdir);
    }

    ImageIO.write(goldenImage, "PNG", fileName);
    return fileName.getPath();
  }

  public static void assertImageSimilar(String imageName,
                                        BufferedImage goldenImage,
                                        BufferedImage image,
                                        float maxPercentDifferent) throws IOException {
    assertTrue("Widths differ too much for " + imageName,
               Math.abs(goldenImage.getWidth() - image.getWidth()) < 2);
    assertTrue("Widths differ too much for " + imageName,
               Math.abs(goldenImage.getHeight() - image.getHeight()) < 2);

    assertEquals(BufferedImage.TYPE_INT_ARGB, image.getType());

    if (goldenImage.getType() != BufferedImage.TYPE_INT_ARGB) {
      BufferedImage temp = new BufferedImage(goldenImage.getWidth(), goldenImage.getHeight(),
                                             BufferedImage.TYPE_INT_ARGB);
      temp.getGraphics().drawImage(goldenImage, 0, 0, null);
      goldenImage = temp;
    }
    assertEquals(BufferedImage.TYPE_INT_ARGB, goldenImage.getType());

    int imageWidth = Math.min(goldenImage.getWidth(), image.getWidth());
    int imageHeight = Math.min(goldenImage.getHeight(), image.getHeight());

    // Blur the images to account for the scenarios where there are pixel
    // differences
    // in where a sharp edge occurs
    // goldenImage = blur(goldenImage, 6);
    // image = blur(image, 6);

    int width = 3 * imageWidth;
    int height = imageHeight;
    BufferedImage deltaImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    Graphics g = deltaImage.getGraphics();

    // Compute delta map
    long delta = 0;
    for (int y = 0; y < imageHeight; y++) {
      for (int x = 0; x < imageWidth; x++) {
        int goldenRgb = goldenImage.getRGB(x, y);
        int rgb = image.getRGB(x, y);
        if (goldenRgb == rgb) {
          deltaImage.setRGB(imageWidth + x, y, 0x00808080);
          continue;
        }

        // If the pixels have no opacity, don't delta colors at all
        if (((goldenRgb & 0xFF000000) == 0) && (rgb & 0xFF000000) == 0) {
          deltaImage.setRGB(imageWidth + x, y, 0x00808080);
          continue;
        }

        int deltaR = ((rgb & 0xFF0000) >>> 16) - ((goldenRgb & 0xFF0000) >>> 16);
        int newR = 128 + deltaR & 0xFF;
        int deltaG = ((rgb & 0x00FF00) >>> 8) - ((goldenRgb & 0x00FF00) >>> 8);
        int newG = 128 + deltaG & 0xFF;
        int deltaB = (rgb & 0x0000FF) - (goldenRgb & 0x0000FF);
        int newB = 128 + deltaB & 0xFF;

        int avgAlpha =
          ((((goldenRgb & 0xFF000000) >>> 24) + ((rgb & 0xFF000000) >>> 24)) / 2) << 24;

        int newRGB = avgAlpha | newR << 16 | newG << 8 | newB;
        deltaImage.setRGB(imageWidth + x, y, newRGB);

        delta += Math.abs(deltaR);
        delta += Math.abs(deltaG);
        delta += Math.abs(deltaB);
      }
    }

    // 3 different colors, 256 color levels
    long total = imageHeight * imageWidth * 3L * 256L;
    float percentDifference = (float)(delta * 100 / (double)total);

    if (percentDifference > maxPercentDifferent) {
      // Expected on the left
      // Golden on the right
      g.drawImage(goldenImage, 0, 0, null);
      g.drawImage(image, 2 * imageWidth, 0, null);

      // Labels
      if (imageWidth > 80) {
        g.setColor(Color.RED);
        g.drawString("Expected", 10, 20);
        g.drawString("Actual", 2 * imageWidth + 10, 20);
      }

      File output = new File(getTempDir(), "delta-" + imageName.replace(File.separatorChar, '_'));
      if (output.exists()) {
        output.delete();
      }
      ImageIO.write(deltaImage, "PNG", output);
      String message =
        String.format("Images differ (by %.1f%%) - see details in %s", percentDifference, output);
      System.out.println(message);
      fail(message);
    }

    g.dispose();
  }

  protected static File getTempDir() {
    if (System.getProperty("os.name").equals("Mac OS X")) {
      return new File("/tmp"); //$NON-NLS-1$
    }

    return new File(System.getProperty("java.io.tmpdir")); //$NON-NLS-1$
  }

  /**
   * Get the location to write missing golden files to
   */
  protected File getTargetDir() {
    // Set $ANDROID_SRC to point to your git AOSP working tree
    String sdk = System.getenv("ANDROID_SRC");
    if (sdk != null) {
      File root = new File(sdk);
      if (root.exists()) {
        File testData = new File(root, getTestDataRelPath().replace('/', File.separatorChar));
        if (testData.exists()) {
          return testData;
        }
      }
    }

    return null;
  }
}