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Added traceImage(), which will doubtless be further optimized, and it

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would sure be nice to have a variant that traces the supplied image rather
than always creating a new one, and more flexibility with respect to the
alpha gradient steps might be nice, but all of that sort of thing will
just have to come later.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1950 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Walter Korman
2002-11-15 09:29:40 +00:00
parent 0c1c441288
commit 275d35ce07
2 changed files with 229 additions and 1 deletions
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src/java/com/threerings/media/image/ImageUtil.java
+154 -1
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@@ -1,5 +1,5 @@
//
// $Id: ImageUtil.java,v 1.17 2002/06/20 17:54:26 mdb Exp $
// $Id: ImageUtil.java,v 1.18 2002/11/15 09:29:40 shaper Exp $
package com.threerings.media.util;
@@ -22,7 +22,10 @@ import java.awt.image.IndexColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.util.Arrays;
import com.samskivert.util.StringUtil;
import com.threerings.media.Log;
/**
@@ -248,6 +251,156 @@ public class ImageUtil
}
}
/**
* Creates and returns a new image consisting of the supplied image
* traced with the given color and thickness.
*/
public static BufferedImage createTracedImage (
BufferedImage src, Color tcolor, int thickness)
{
return createTracedImage(src, tcolor, thickness, 1.0f, 1.0f);
}
/**
* Creates and returns a new image consisting of the supplied image
* traced with the given color, thickness and alpha transparency.
*/
public static BufferedImage createTracedImage (
BufferedImage src, Color tcolor, int thickness,
float startAlpha, float endAlpha)
{
Raster srcdata = src.getData();
if (srcdata.getNumBands() != 4) {
throw new IllegalArgumentException(
"Can't trace an image with no transparency " +
"[image=" + src + "].");
}
// create the destination image
int wid = src.getWidth(null), hei = src.getHeight(null);
BufferedImage dest = createImage(wid, hei, Transparency.TRANSLUCENT);
// prepare various bits of working data
int srcTrans = src.getColorModel().getTransparency();
int[] tpixel = new int[] {
tcolor.getRed(), tcolor.getGreen(), tcolor.getBlue(),
(int)(startAlpha * 255)};
int[] curpixel = new int[4];
int[] workpixel = new int[4];
WritableRaster destdata = dest.getRaster();
boolean[] traced = new boolean[wid * hei];
int stepAlpha = (thickness <= 1) ? 0 :
(int)(((startAlpha - endAlpha) * 255) / (thickness - 1));
// TODO: this could be made more efficient, e.g., if we made four
// passes through the image in a vertical scan, horizontal scan,
// and opposing diagonal scans, making sure each non-transparent
// pixel found during each scan is traced on both sides of the
// respective scan direction. for now, we just naively check all
// eight pixels surrounding each pixel in the image and fill the
// center pixel with the tracing color if it's transparent but has
// a non-transparent pixel around it.
for (int tt = 0; tt < thickness; tt++) {
if (tt > 0) {
// clear out the array of pixels traced this go-around
Arrays.fill(traced, false);
// use the destination image as our new source
srcdata = dest.getData();
// decrement the trace pixel alpha-level
tpixel[3] = Math.max(0, tpixel[3] - stepAlpha);
}
for (int yy = 0; yy < hei; yy++) {
for (int xx = 0; xx < wid; xx++) {
// get the pixel we're checking
srcdata.getPixel(xx, yy, curpixel);
if (!isTransparentPixel(curpixel)) {
// copy any pixel that isn't transparent
if (tt == 0 && srcTrans == Transparency.BITMASK) {
// give any non-transparent pixel full opacity
curpixel[3] = 255;
}
destdata.setPixel(xx, yy, curpixel);
} else if (bordersNonTransparentPixel(
srcdata, wid, hei, traced,
xx, yy, workpixel)) {
destdata.setPixel(xx, yy, tpixel);
// note that we traced this pixel this pass so
// that it doesn't impact other-pixel borderedness
traced[(yy*wid)+xx] = true;
}
}
}
}
return dest;
}
/**
* Returns whether the given pixel is bordered by any non-transparent
* pixel.
*/
protected static boolean bordersNonTransparentPixel (
Raster data, int wid, int hei, boolean[] traced,
int x, int y, int[] workpixel)
{
// check the three-pixel row above the pixel
if (y > 0) {
for (int rxx = x - 1; rxx <= x + 1; rxx++) {
if (rxx < 0 || rxx >= wid || traced[((y-1)*wid)+rxx]) {
continue;
}
data.getPixel(rxx, y - 1, workpixel);
if (!isTransparentPixel(workpixel)) {
return true;
}
}
}
// check the pixel to the left
if (x > 0 && !traced[(y*wid)+(x-1)]) {
data.getPixel(x - 1, y, workpixel);
if (!isTransparentPixel(workpixel)) {
return true;
}
}
// check the pixel to the right
if (x < wid - 1 && !traced[(y*wid)+(x+1)]) {
data.getPixel(x + 1, y, workpixel);
if (!isTransparentPixel(workpixel)) {
return true;
}
}
// check the three-pixel row below the pixel
if (y < hei - 1) {
for (int rxx = x - 1; rxx <= x + 1; rxx++) {
if (rxx < 0 || rxx >= wid || traced[((y+1)*wid)+rxx]) {
continue;
}
data.getPixel(rxx, y + 1, workpixel);
if (!isTransparentPixel(workpixel)) {
return true;
}
}
}
return false;
}
/**
* Returns whether the given pixel is completely transparent.
*/
protected static boolean isTransparentPixel (int[] pixel)
{
return (pixel[3] == 0);
}
/**
* Create an image using the alpha channel from the first and the RGB
* values from the second.
tests/src/java/com/threerings/media/util/TraceViz.java
+75
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@@ -0,0 +1,75 @@
//
// $Id: TraceViz.java,v 1.1 2002/11/15 09:29:40 shaper Exp $
package com.threerings.media.util;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import com.samskivert.swing.VGroupLayout;
import com.samskivert.swing.util.SwingUtil;
import com.threerings.media.Log;
/**
* Simple application for testing image trace functionality.
*/
public class TraceViz
{
public TraceViz (String[] args)
throws IOException
{
_frame = new JFrame();
_frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel content = (JPanel)_frame.getContentPane();
content.setBackground(Color.white);
content.setLayout(new VGroupLayout());
// create a compatible image
BufferedImage image = ImageIO.read(new File(args[0]));
BufferedImage cimage = ImageUtil.createImage(
image.getWidth(null), image.getHeight(null));
Graphics g = cimage.getGraphics();
g.drawImage(image, 0, 0, null);
g.dispose();
Image timage = ImageUtil.createTracedImage(
cimage, Color.red, 5, 0.4f, 0.1f);
content.add(new JLabel(new ImageIcon(cimage)));
content.add(new JLabel(new ImageIcon(timage)));
}
public void run ()
{
_frame.pack();
SwingUtil.centerWindow(_frame);
_frame.show();
}
public static void main (String[] args)
{
try {
TraceViz app = new TraceViz(args);
app.run();
} catch (Exception e) {
Log.warning("Failed to run application: " + e);
Log.logStackTrace(e);
}
}
protected JFrame _frame;
}