Rework grayscale and resizing ImageFunctions for ImageComparator

Fix documentation for IVisualStateProvider
Fix coding issues

Author: mialeska

src/main/java/aquality/selenium/core/visualization/IVisualStateProvider.java

@@ -30,7 +30,6 @@ public interface IVisualStateProvider {
      * Gets the difference between the image of the element and the provided image using {@link IImageComparator}.
      * @param theOtherOne the image to compare the element with.
      * @param threshold how big a difference will be ignored as a percentage - value between 0 and 1.
-     *                  If the value is null, the default value is got from {@link aquality.selenium.core.configurations.IVisualConfiguration}.
      * @return the difference between the two images as a percentage  - value between 0 and 1.
      */
     float getDifference(Image theOtherOne, float threshold);

src/main/java/aquality/selenium/core/visualization/ImageComparator.java

@@ -1,25 +1,39 @@
 package aquality.selenium.core.visualization;
 
+import aquality.selenium.core.configurations.IVisualConfiguration;
+import com.google.inject.Inject;
+
 import java.awt.*;
 import java.awt.image.BufferedImage;
 
 public class ImageComparator implements IImageComparator {
-    private static final int DEFAULT_THRESHOLD = 3;
     private static final int THRESHOLD_DIVISOR = 255;
-    private final int comparisonHeight = 16;
-    private final int comparisonWidth = 16;
+    private final IVisualConfiguration visualConfiguration;
+
+    @Inject
+    public ImageComparator(IVisualConfiguration visualConfiguration) {
+        this.visualConfiguration = visualConfiguration;
+    }
+
+    private int getComparisonHeight() {
+        return visualConfiguration.getComparisonHeight();
+    }
+
+    private int getComparisonWidth() {
+        return visualConfiguration.getComparisonWidth();
+    }
 
     public float percentageDifference(Image thisOne, Image theOtherOne, float threshold) {
         if (threshold < 0 || threshold > 1) {
             throw new IllegalArgumentException(String.format("Threshold should be between 0 and 1, but was [%s]", threshold));
         }
 
-        int intThreshold = Float.valueOf(threshold * THRESHOLD_DIVISOR).intValue();
+        int intThreshold = (int) (threshold * THRESHOLD_DIVISOR);
         return percentageDifference(thisOne, theOtherOne, intThreshold);
     }
 
     public float percentageDifference(Image thisOne, Image theOtherOne) {
-        return percentageDifference(thisOne, theOtherOne, DEFAULT_THRESHOLD);
+        return percentageDifference(thisOne, theOtherOne, visualConfiguration.getDefaultThreshold());
     }
 
     protected float percentageDifference(Image thisOne, Image theOtherOne, int threshold) {
@@ -35,16 +49,16 @@ protected float percentageDifference(Image thisOne, Image theOtherOne, int thres
             }
         }
 
-        return diffPixels / (float) (comparisonWidth * comparisonHeight);
+        return diffPixels / (float) (getComparisonWidth() * getComparisonHeight());
     }
 
     protected int[][] getDifferences(Image thisOne, Image theOtherOne) {
         int[][] firstGray = getResizedGrayScaleValues(thisOne);
         int[][] secondGray = getResizedGrayScaleValues(theOtherOne);
 
-        int[][] differences = new int[comparisonWidth][comparisonHeight];
-        for (int y = 0; y < comparisonHeight; y++) {
-            for (int x = 0; x < comparisonWidth; x++) {
+        int[][] differences = new int[getComparisonWidth()][getComparisonHeight()];
+        for (int y = 0; y < getComparisonHeight(); y++) {
+            for (int x = 0; x < getComparisonWidth(); x++) {
                 differences[x][y] = (byte) Math.abs(firstGray[x][y] - secondGray[x][y]);
             }
         }
@@ -53,13 +67,11 @@ protected int[][] getDifferences(Image thisOne, Image theOtherOne) {
     }
 
     protected int[][] getResizedGrayScaleValues(Image image) {
-        BufferedImage resizedImage = new BufferedImage(comparisonWidth, comparisonHeight, BufferedImage.TYPE_BYTE_GRAY);
-        Graphics2D graphics2D = resizedImage.createGraphics();
-        graphics2D.drawImage(image, 0, 0, comparisonWidth, comparisonHeight, null);
-        graphics2D.dispose();
-        int[][] grayScale = new int[comparisonWidth][comparisonHeight];
-        for (int y = 0; y < comparisonHeight; y++) {
-            for (int x = 0; x < comparisonWidth; x++) {
+        BufferedImage resizedImage = ImageFunctions.resize(image, getComparisonWidth(), getComparisonHeight());
+        BufferedImage grayImage = ImageFunctions.grayscale(resizedImage);
+        int[][] grayScale = new int[grayImage.getWidth()][grayImage.getHeight()];
+        for (int y = 0; y < grayImage.getHeight(); y++) {
+            for (int x = 0; x < grayImage.getWidth(); x++) {
                 int pixel = resizedImage.getRGB(x, y);
                 int red = (pixel >> 16) & 0xff;
                 grayScale[x][y] = Math.abs(red);

src/main/java/aquality/selenium/core/visualization/ImageFunctions.java

@@ -19,8 +19,13 @@
  * Image and screenshot extensions.
  */
 public class ImageFunctions {
+    private ImageFunctions() throws InstantiationException {
+        throw new InstantiationException("Static ImageFunctions should not be initialized");
+    }
+
     /**
      * Represents given element's screenshot as an image.
+     *
      * @param element given element.
      * @return image object.
      */
@@ -30,6 +35,7 @@ public static BufferedImage getScreenshotAsImage(IElement element) {
 
     /**
      * Represents given element's screenshot as an image.
+     *
      * @param element given element.
      * @return image object.
      */
@@ -45,17 +51,55 @@ public static BufferedImage getScreenshotAsImage(RemoteWebElement element) {
 
     /**
      * Represents dimension of the given image.
+     *
      * @param image given image.
      * @return size of the given image.
      */
     public static Dimension getSize(Image image) {
         if (image instanceof RenderedImage) {
             RenderedImage renderedImage = (RenderedImage) image;
             return new Dimension(renderedImage.getWidth(), renderedImage.getHeight());
-        }
-        else {
+        } else {
             return new Dimension(image.getWidth(null), image.getHeight(null));
         }
+    }
 
+    /**
+     * Gray-scaling the image.
+     *
+     * @param image source image.
+     * @return gray-scaled image.
+     */
+    public static BufferedImage grayscale(BufferedImage image) {
+        BufferedImage result = new BufferedImage(image.getWidth(), image.getHeight(), image.getType());
+        for (int y = 0; y < result.getHeight(); y++) {
+            for (int x = 0; x < result.getWidth(); x++) {
+                int pixel = image.getRGB(x, y);
+                int a = (pixel >> 24) & 0xff;
+                int r = (pixel >> 16) & 0xff;
+                int g = (pixel >> 8) & 0xff;
+                int b = pixel & 0xff;
+                int average = (r + g + b) / 3;
+                pixel = (a << 24) | (average << 16) | (average << 8) | average;
+                result.setRGB(x, y, pixel);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Resizes image giving higher priority to image smoothness than scaling speed.
+     * @param image source image.
+     * @param width target width.
+     * @param height target height.
+     * @return resized image.
+     */
+    public static BufferedImage resize(Image image, int width, int height) {
+        BufferedImage resizedImage = new BufferedImage(width, height, TYPE_INT_RGB);
+        Graphics graphics = resizedImage.getGraphics();
+        Image scaledImage = image.getScaledInstance(width, height, Image.SCALE_SMOOTH);
+        graphics.drawImage(scaledImage, 0, 0, width, height, null);
+        graphics.dispose();
+        return resizedImage;
     }
 }

src/test/java/tests/visualization/VisualStateProviderTests.java

@@ -2,9 +2,11 @@
 
 import aquality.selenium.core.visualization.IVisualStateProvider;
 import aquality.selenium.core.visualization.ImageFunctions;
+import aquality.selenium.core.waitings.IConditionalWait;
 import org.testng.Assert;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
+import tests.applications.browser.AqualityServices;
 import tests.applications.browser.ITheInternetPageTest;
 import theinternet.DynamicLoadingForm;
 import theinternet.TheInternetPage;
@@ -81,7 +83,8 @@ public void testGetPercentageDifferenceForDifferentElementsWithFullThreshold() {
     public void testGetPercentageDifferenceForSimilarElements() throws InterruptedException {
         startLoading();
         Image firstImage = getLoadingVisual().getImage();
-        Thread.sleep(100);
+        AqualityServices.get(IConditionalWait.class).waitFor(
+                () -> firstImage.getHeight(null) < getLoadingVisual().getSize().getHeight());
         Assert.assertNotEquals(getLoadingVisual().getDifference(firstImage, 0), 0);
         Assert.assertTrue(getLoadingVisual().getDifference(firstImage, 0.2f) <= 0.3);
         Assert.assertTrue(getLoadingVisual().getDifference(firstImage, 0.4f) <= 0.2);