1 files changed, 185 insertions, 0 deletions
diff --git a/dropShadow/ShadowRenderer.java b/dropShadow/ShadowRenderer.java
new file mode 100644
index 0000000..d80d2c8
--- /dev/null
+++ b/dropShadow/ShadowRenderer.java
@@ -0,0 +1,185 @@
+package dropShadow;
+
+import java.awt.Color;
+import java.awt.image.BufferedImage;
+
+public class ShadowRenderer {
+
+    // size of the shadow in pixels (defines the fuzziness)
+    private int size = 5;
+
+    // opacity of the shadow
+    private float opacity = 0.5f;
+
+    // color of the shadow
+    private Color color = Color.BLACK;
+
+    public ShadowRenderer() {
+        this(5, 0.5f, Color.BLACK);
+    }
+
+    public ShadowRenderer(final int size, final float opacity, final Color color) {
+        this.size = size;
+        this.opacity = opacity;
+        this.color = color;
+    }
+
+    public Color getColor() {
+        return color;
+    }
+
+    public float getOpacity() {
+        return opacity;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public BufferedImage createShadow(final BufferedImage image) {
+        // Written by Sesbastien Petrucci
+        int shadowSize = size * 2;
+
+        int srcWidth = image.getWidth();
+        int srcHeight = image.getHeight();
+
+        int dstWidth = srcWidth + shadowSize;
+        int dstHeight = srcHeight + shadowSize;
+
+        int left = size;
+        int right = shadowSize - left;
+
+        int yStop = dstHeight - right;
+
+        int shadowRgb = color.getRGB() & 0x00FFFFFF;
+        int[] aHistory = new int[shadowSize];
+        int historyIdx;
+
+        int aSum;
+
+        BufferedImage dst = new BufferedImage(dstWidth, dstHeight,
+                BufferedImage.TYPE_INT_ARGB);
+
+        int[] dstBuffer = new int[dstWidth * dstHeight];
+        int[] srcBuffer = new int[srcWidth * srcHeight];
+
+        GraphicsUtilities.getPixels(image, 0, 0, srcWidth, srcHeight, srcBuffer);
+
+        int lastPixelOffset = right * dstWidth;
+        float hSumDivider = 1.0f / shadowSize;
+        float vSumDivider = opacity / shadowSize;
+
+        int[] hSumLookup = new int[256 * shadowSize];
+        for (int i = 0; i < hSumLookup.length; i++) {
+            hSumLookup[i] = (int) (i * hSumDivider);
+        }
+
+        int[] vSumLookup = new int[256 * shadowSize];
+        for (int i = 0; i < vSumLookup.length; i++) {
+            vSumLookup[i] = (int) (i * vSumDivider);
+        }
+
+        int srcOffset;
+
+        // horizontal pass : extract the alpha mask from the source picture and
+        // blur it into the destination picture
+        for (int srcY = 0, dstOffset = left * dstWidth; srcY < srcHeight; srcY++) {
+
+            // first pixels are empty
+            for (historyIdx = 0; historyIdx < shadowSize;) {
+                aHistory[historyIdx++] = 0;
+            }
+
+            aSum = 0;
+            historyIdx = 0;
+            srcOffset = srcY * srcWidth;
+
+            // compute the blur average with pixels from the source image
+            for (int srcX = 0; srcX < srcWidth; srcX++) {
+
+                int a = hSumLookup[aSum];
+                dstBuffer[dstOffset++] = a << 24;   // store the alpha value only
+                // the shadow color will be added in the next pass
+
+                aSum -= aHistory[historyIdx]; // substract the oldest pixel from the sum
+
+                // extract the new pixel ...
+                a = srcBuffer[srcOffset + srcX] >>> 24;
+                aHistory[historyIdx] = a;   // ... and store its value into history
+                aSum += a;                  // ... and add its value to the sum
+
+                if (++historyIdx >= shadowSize) {
+                    historyIdx -= shadowSize;
+                }
+            }
+
+            // blur the end of the row - no new pixels to grab
+            for (int i = 0; i < shadowSize; i++) {
+
+                int a = hSumLookup[aSum];
+                dstBuffer[dstOffset++] = a << 24;
+
+                // substract the oldest pixel from the sum ... and nothing new to add !
+                aSum -= aHistory[historyIdx];
+
+                if (++historyIdx >= shadowSize) {
+                    historyIdx -= shadowSize;
+                }
+            }
+        }
+
+        // vertical pass
+        for (int x = 0, bufferOffset = 0; x < dstWidth; x++, bufferOffset = x) {
+
+            aSum = 0;
+
+            // first pixels are empty
+            for (historyIdx = 0; historyIdx < left;) {
+                aHistory[historyIdx++] = 0;
+            }
+
+            // and then they come from the dstBuffer
+            for (int y = 0; y < right; y++, bufferOffset += dstWidth) {
+                int a = dstBuffer[bufferOffset] >>> 24;         // extract alpha
+                aHistory[historyIdx++] = a;                     // store into history
+                aSum += a;                                      // and add to sum
+            }
+
+            bufferOffset = x;
+            historyIdx = 0;
+
+            // compute the blur avera`ge with pixels from the previous pass
+            for (int y = 0; y < yStop; y++, bufferOffset += dstWidth) {
+
+                int a = vSumLookup[aSum];
+                dstBuffer[bufferOffset] = a << 24 | shadowRgb;  // store alpha value + shadow color
+
+                aSum -= aHistory[historyIdx];   // substract the oldest pixel from the sum
+
+                a = dstBuffer[bufferOffset + lastPixelOffset] >>> 24;   // extract the new pixel ...
+                aHistory[historyIdx] = a;                               // ... and store its value into history
+                aSum += a;                                              // ... and add its value to the sum
+
+                if (++historyIdx >= shadowSize) {
+                    historyIdx -= shadowSize;
+                }
+            }
+
+            // blur the end of the column - no pixels to grab anymore
+            for (int y = yStop; y < dstHeight; y++, bufferOffset += dstWidth) {
+
+                int a = vSumLookup[aSum];
+                dstBuffer[bufferOffset] = a << 24 | shadowRgb;
+
+                aSum -= aHistory[historyIdx];   // substract the oldest pixel from the sum
+
+                if (++historyIdx >= shadowSize) {
+                    historyIdx -= shadowSize;
+                }
+            }
+        }
+
+        GraphicsUtilities.setPixels(dst, 0, 0, dstWidth, dstHeight, dstBuffer);
+        return dst;
+    }
+}