implement ignoring fully transparent sprites

src/com/gpl/rpg/atcontentstudio/ui/sprites/SpriteChooser.java

@@ -1,29 +1,20 @@
 package com.gpl.rpg.atcontentstudio.ui.sprites;
 
-import java.awt.BorderLayout;
+import java.awt.*;
-import java.awt.GridBagConstraints;
-import java.awt.GridBagLayout;
-import java.awt.Image;
-import java.awt.Point;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.awt.image.BufferedImage;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-
+import javax.swing.*;
-import javax.swing.ButtonGroup;
-import javax.swing.ImageIcon;
-import javax.swing.JDialog;
-import javax.swing.JPanel;
-import javax.swing.JScrollPane;
-import javax.swing.JToggleButton;
-import javax.swing.ScrollPaneConstants;
 
 import com.gpl.rpg.atcontentstudio.ATContentStudio;
 import com.gpl.rpg.atcontentstudio.model.Project;
 import com.gpl.rpg.atcontentstudio.model.sprites.Spritesheet;
 import com.gpl.rpg.atcontentstudio.model.sprites.Spritesheet.Category;
+import com.gpl.rpg.atcontentstudio.utils.SpriteUtils;
 
 
 public class SpriteChooser extends JDialog {
@@ -34,8 +25,8 @@ public class SpriteChooser extends JDialog {
 	private static final int STD_HEIGHT = 32;
 	private static final int MAX_PER_ROW = 10;
 
-	public static Map<Project, Map<Spritesheet.Category, SpriteChooser>> cache = new LinkedHashMap<Project, Map<Spritesheet.Category,SpriteChooser>>();
+	public static Map<Project, Map<Spritesheet.Category, SpriteChooser>> cache = new LinkedHashMap<Project, Map<Spritesheet.Category, SpriteChooser>>();
-	public static Map<Project, Map<Spritesheet.Category, List<Spritesheet>>> cacheValidator = new LinkedHashMap<Project, Map<Category,List<Spritesheet>>>();
+	public static Map<Project, Map<Spritesheet.Category, List<Spritesheet>>> cacheValidator = new LinkedHashMap<Project, Map<Category, List<Spritesheet>>>();
 
 
 	public static SpriteChooser getChooser(Project proj, Spritesheet.Category category) {
@@ -46,13 +37,13 @@ public class SpriteChooser extends JDialog {
 			cache.get(proj).put(category, new SpriteChooser(proj, category));
 		} else {
 			List<Spritesheet> spritesheets = new ArrayList<Spritesheet>();
-			for (int i=0; i<proj.getSpritesheetCount(); i++) {
+			for (int i = 0; i < proj.getSpritesheetCount(); i++) {
 				Spritesheet sheet = proj.getSpritesheet(i);
 				if (sheet.category == category) {
 					spritesheets.add(sheet);
 				}
 			}
-			if ( !spritesheets.equals(cacheValidator.get(proj).get(category)) ) {
+			if (!spritesheets.equals(cacheValidator.get(proj).get(category))) {
 				cache.get(proj).put(category, new SpriteChooser(proj, category));
 			}
 		}
@@ -78,7 +69,7 @@ public class SpriteChooser extends JDialog {
 		setTitle("Select a sprite");
 		setModalityType(ModalityType.APPLICATION_MODAL);
 		List<Spritesheet> spritesheets = new ArrayList<Spritesheet>();
-		for (int i=0; i<proj.getSpritesheetCount(); i++) {
+		for (int i = 0; i < proj.getSpritesheetCount(); i++) {
 			Spritesheet sheet = proj.getSpritesheet(i);
 			if (sheet.category == category) {
 				spritesheets.add(sheet);
@@ -106,11 +97,14 @@ public class SpriteChooser extends JDialog {
 		Point nextFreeSlot = new Point(0, 0);
 
 		int i;
-		Image img;
+		BufferedImage img;
 		group = new ButtonGroup();
 		for (Spritesheet sheet : spritesheets) {
-			i = 0;
+            i = -1;
-			while ((img = sheet.getImage(i)) != null) {
+            while ((img = sheet.getImage(++i)) != null) {
+                if (SpriteUtils.checkIsImageEmpty(img)) {
+                    continue;
+                }
 				IconButton button = new IconButton(img, sheet.id, i);
 				group.add(button);
 				if (sheet.spriteWidth == STD_WIDTH && sheet.spriteHeight == STD_HEIGHT) {
@@ -120,7 +114,7 @@ public class SpriteChooser extends JDialog {
 						c.gridx = 0;
 						c.gridy++;
 					}
-					nextFreeSlot.setLocation(c.gridx,  c.gridy);
+					nextFreeSlot.setLocation(c.gridx, c.gridy);
 				} else {
 					c.gridwidth = (sheet.spriteWidth / STD_WIDTH) + (sheet.spriteWidth % STD_WIDTH == 0 ? 0 : 1);
 					c.gridheight = (sheet.spriteHeight / STD_HEIGHT) + (sheet.spriteHeight % STD_HEIGHT == 0 ? 0 : 1);
@@ -157,9 +151,8 @@ public class SpriteChooser extends JDialog {
 						c.gridx = 0;
 						c.gridy++;
 					}
-					nextFreeSlot.setLocation(c.gridx,  c.gridy);
+					nextFreeSlot.setLocation(c.gridx, c.gridy);
 				}
-				i++;
 			}
 		}
 
@@ -232,12 +225,12 @@ public class SpriteChooser extends JDialog {
 			super(new ImageIcon(img));
 			this.sheetId = sheetId;
 			this.spriteIndex = spriteIndex;
-			setToolTipText(sheetId+":"+spriteIndex);
+			setToolTipText(sheetId + ":" + spriteIndex);
 			addActionListener(new ActionListener() {
 				@Override
 				public void actionPerformed(ActionEvent e) {
 					if (IconButton.this.isSelected()) {
-						selectedIconId = IconButton.this.sheetId+":"+IconButton.this.spriteIndex;
+						selectedIconId = IconButton.this.sheetId + ":" + IconButton.this.spriteIndex;
 						SpriteChooser.this.setVisible(false);
 						SpriteChooser.this.dispose();
 						if (listener != null) listener.iconSelected(selectedIconId);

src/com/gpl/rpg/atcontentstudio/utils/SpriteUtils.java

@@ -0,0 +1,34 @@
+package com.gpl.rpg.atcontentstudio.utils;
+
+import java.awt.image.BufferedImage;
+import java.awt.image.WritableRaster;
+
+public final class SpriteUtils {
+
+	/**
+	 * Check if the image is empty (transparent )
+	 *
+	 * @param img The image to check
+	 * @return true if the image is empty
+	 */
+	public static boolean checkIsImageEmpty(BufferedImage img) {
+		int width = img.getWidth(null);
+		int height = img.getHeight(null);
+		WritableRaster raster = img.getAlphaRaster();
+		if (raster == null) {
+			return false;
+		}
+		for (int x = 0; x < width; x++) {
+			for (int y = 0; y < height; y++) {
+				//get pixel alpha value
+				int alpha = raster.getSample(x, y, 0);
+				//if alpha is not 0 then the pixel is not transparent
+				if (alpha != 0) {
+					return false;
+				}
+			}
+		}
+		//no non-transparent pixel found
+		return true;
+	}
+}