Merge pull request #40 from mac-comp127/int-image-pixels

Added ability to convert Images to/from 32-bit ARGB int[]

Author: pcantrell

src/edu/macalester/graphics/Image.java

@@ -19,9 +19,9 @@
 /**
  * A bitmap image that can be drawn to the screen.
  * <p>
- * An image’s {@link getPosition() position} is the upper left corner of its bounding box.
+ * An image’s {@link #getPosition() position} is the upper left corner of its bounding box.
  * Its size is the size of the underying image file by default, but you can shrink it using
- * {@link setMaxWidth(double) setMaxWidth()} and {@link setMaxHeight(double) setMaxHeight()}.
+ * {@link #setMaxWidth(double) setMaxWidth()} and {@link #setMaxHeight(double) setMaxHeight()}.
  *
  * @author Bret Jackson, Paul Cantrell
  */
@@ -139,7 +139,7 @@ public Image(int width, int height, float[] pixels, PixelFormat format) {
     }
 
     /**
-     * Creates a new image using raw pixel data from the given array. This method interprets bytes
+     * Creates a new image using raw pixel data from the given array. This interprets bytes
      * as unsigned: zero intensity is 0, and full intensity is 255 (but Java represents this as -1,
      * because the language does not have unsigned primitive types).
      * There is one array element per color channel, with channels interleaved
@@ -157,13 +157,23 @@ public Image(int width, int height, byte[] pixels, PixelFormat format) {
         this(format.makeBufferedImage(pixels, width, height));
     }
 
+    /**
+     * Creates a new image using raw pixel data from the given array, one int per pixel. Each pixel
+     * is in 32-bit ARGB format.
+     *
+     * @param width Image width in pixels
+     * @param height Image height in pixels
+     * @param pixels Raw pixel data. Length must exactly match the number of required samples.
+     */
+    public Image(int width, int height, int[] pixels) {
+        this(createBufferFromRawPixelData(width, height, pixels));
+    }
+
     /**
      * Creates a bitmap image from the given BufferedImage, positioned at (0, 0).
      * Note that changing the BufferedImage externally does not automatically 
      * force it to redraw. You will need to call {@link CanvasWindow#draw()}
      * to see the changes.
-     * 
-     * @param image
      */
     public Image(BufferedImage image){
         this(0, 0, image);
@@ -173,12 +183,10 @@ public Image(BufferedImage image){
      * Creates a bitmap image from the given BufferedImage. Note that changing
      * the BufferedImage externally does not automatically force it to redraw.
      * You will need to call {@link CanvasWindow#draw()} to see the changes.
-     * 
-     * @param image
      */
     public Image(double x, double y, BufferedImage image){
         setPosition(x, y);
-        this.path = "In memory BufferedImage@"+Integer.toHexString(image.hashCode());
+        this.path = "In-memory BufferedImage@"+Integer.toHexString(image.hashCode());
         this.img = image;
     }
 
@@ -282,7 +290,8 @@ private double getScaleToFit() {
      * produces results that correspond poorly to perceived brightness.
      *
      * @see #Image(int,int,byte[],PixelFormat)
-     * @see #toFloatArray(PixelFormat) 
+     * @see #toFloatArray(PixelFormat)
+     * @see #toIntArray()
      */
     public byte[] toByteArray(PixelFormat format) {
         return format.makeByteArray(img);
@@ -308,6 +317,37 @@ public float[] toFloatArray(PixelFormat format) {
         return floats;
     }
 
+    /**
+     * Returns the pixels in this image as an array of ints, one int per <b>pixel</b>. Pixels use
+     * 32-bit ARGB encoding.
+     * <p>
+     * Note that the other methods that convert images to arrays return one array entry per
+     * <b>color channel</b>, while this method returns one array entry <b>per pixel</b>.
+     *
+     * @see #Image(int,int,byte[],PixelFormat)
+     * @see #toFloatArray(PixelFormat)
+     */
+    public int[] toIntArray() {
+        return getRawPixelData(img);
+    }
+
+    private static int[] getRawPixelData(BufferedImage buf) {
+        return buf.getRGB(0, 0, buf.getWidth(), buf.getHeight(), null, 0, buf.getWidth());
+    }
+
+    private static BufferedImage createBufferFromRawPixelData(int width, int height, int[] pixels) {
+        int expectedArrayLen = width * height;
+        if (pixels.length != expectedArrayLen) {
+            throw new IllegalArgumentException(
+                "Invalid input array length: expected "  + width + " w * " + height + " h = "
+                + expectedArrayLen + ", but got " + pixels.length);
+        }
+
+        BufferedImage buf = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+        buf.setRGB(0, 0, width, height, pixels, 0, width);
+        return buf;
+    }
+
     @Override
     protected Object getEqualityAttributes() {
         return List.of(path, maxWidth, maxHeight);  // Not ideally performant, but life goes on
@@ -407,9 +447,9 @@ private BufferedImage makeBufferedImage(
         }
 
         private byte[] makeByteArray(BufferedImage buf) {
-            int width = buf.getWidth(), height = buf.getHeight();
-            int[] rawData = buf.getRGB(0, 0, width, height, null, 0, width);
+            int[] rawData = getRawPixelData(buf);
 
+            int width = buf.getWidth(), height = buf.getHeight();
             byte[] pixels = new byte[width * height * externalChans];
             int i = 0;
             for(int pix : rawData) {

test/edu/macalester/graphics/ImageTest.java

@@ -93,7 +93,9 @@ void pixelsConstructorsCheckBounds() {
         for (var ctorCall : List.of((Executable)
             () -> new Image(2, 3, new float[18], Image.PixelFormat.GRAYSCALE),  // too large
             () -> new Image(3, 2, new float[6], Image.PixelFormat.RGB),         // too small
-            () -> new Image(3, 2, new byte[18], Image.PixelFormat.ARGB)         // too small
+            () -> new Image(3, 2, new byte[18], Image.PixelFormat.ARGB),        // too small
+            () -> new Image(3, 2, new int[7]),                                  // too large
+            () -> new Image(3, 2, new int[5])                                   // too small
         )) {
             assertThrows(IllegalArgumentException.class, ctorCall);
         }
@@ -213,6 +215,22 @@ void imageFileProcessing() {
             Image.PixelFormat.RGB);
     }
 
+    @RenderingTest(width=200, height=200, modes = { PLAIN })
+    void imageFileProcessingWithInts() {
+        Image original = new Image(FOXFLOWER_IMAGE);
+        int[] src = original.toIntArray();
+        int[] dst = new int[src.length];
+
+        for(int i = 0; i < src.length; i++) {
+            dst[i] = src[src.length - i - 1] ^ (i * 17);
+        }
+
+        image = new Image(
+            original.getImageWidth(),
+            original.getImageHeight(),
+            dst);
+    }
+
     @RenderingTest(height=200, modes = { PLAIN })
     void colorPixelConversionToGrayscaleArray() {
         Image colorImage = new Image(FOXBOT_IMAGE);