Version 19, May 2018

[GpsPrune.git] / tim / prune / gui / ImageUtils.java

diff --git a/tim/prune/gui/ImageUtils.java b/tim/prune/gui/ImageUtils.java
index 4b46959f55c575d46fe0670851925fd91580cdf6..c3c4c2088d796e71d9ca2bcf9aaec1c6f35b9076 100644 (file)
--- a/tim/prune/gui/ImageUtils.java
+++ b/tim/prune/gui/ImageUtils.java
@@ -2,6 +2,7 @@ package tim.prune.gui;
 
 import java.awt.Dimension;
 import java.awt.Graphics;
+import java.awt.Graphics2D;
 import java.awt.Image;
 import java.awt.image.BufferedImage;
 import java.awt.image.ConvolveOp;
@@ -38,6 +39,9 @@ public abstract class ImageUtils
         */
        public static BufferedImage createScaledImage(Image inImage, int inWidth, int inHeight)
        {
+               if (inWidth <= 0 || inHeight <= 0) {
+                       return null;
+               }
                // create smaller image and force its loading
                Image smallerImage = inImage.getScaledInstance(inWidth, inHeight, Image.SCALE_SMOOTH);
                Image tempImage = new ImageIcon(smallerImage).getImage();
@@ -69,18 +73,67 @@ public abstract class ImageUtils
         */
        public static Dimension getThumbnailSize(int inOrigWidth, int inOrigHeight, int inMaxWidth, int inMaxHeight)
        {
-               if (inMaxWidth <= 0 || inMaxHeight <= 0)
-               {
-                       //System.out.println("Can't do it - maxwidth=" + inMaxWidth + ", maxheight=" + inMaxHeight);
-                       return new Dimension(0,0);
-               }
+               if (inMaxWidth <= 0 || inMaxHeight <= 0) {return new Dimension(1, 1);}
                // work out maximum zoom ratio available so that thumbnail isn't too big
                double xZoom = inMaxWidth * 1.0 / inOrigWidth;
                double yZoom = inMaxHeight * 1.0 / inOrigHeight;
                double zoom = (xZoom > yZoom?yZoom:xZoom);
                // Don't make thumbnail bigger than picture
                if (zoom > 1.0) {return new Dimension(inOrigWidth, inOrigHeight);}
+
                // calculate new width and height
-               return new Dimension ((int) (zoom * inOrigWidth), (int) (zoom * inOrigHeight));
+               final int xSize = (int) (zoom * inOrigWidth);
+               final int ySize = (int) (zoom * inOrigHeight);
+               if (xSize <= 0 || ySize <= 0) {return new Dimension(1, 1);}
+               return new Dimension (xSize, ySize);
+       }
+
+
+       /**
+        * Create a new image by rotating and scaling the given one
+        * @param inImage input image
+        * @param inMaxWidth maximum width of output image
+        * @param inMaxHeight maximum height of output image
+        * @param inRotationDegrees number of degrees to rotate clockwise (0, 90, 180 or 270)
+        * @return rotated, scaled image
+        */
+       public static BufferedImage rotateImage(Image inImage, int inMaxWidth, int inMaxHeight, int inRotationDegrees)
+       {
+               // Create scaled image of suitable size
+               boolean isRotated = (inRotationDegrees % 180 != 0);
+               int origWidth = inImage.getWidth(null);
+               int origHeight = inImage.getHeight(null);
+               int thumbWidth = isRotated?origHeight:origWidth;
+               int thumbHeight = isRotated?origWidth:origHeight;
+               Dimension scaledSize = getThumbnailSize(thumbWidth, thumbHeight, inMaxWidth, inMaxHeight);
+               BufferedImage result = new BufferedImage(scaledSize.width, scaledSize.height, BufferedImage.TYPE_INT_RGB);
+               // Do different things according to rotation angle (a bit messy, sorry!)
+               if (inRotationDegrees == 0)
+               {
+                       // Not rotated, so just copy image directly
+                       result.getGraphics().drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
+               }
+               else
+               {
+                       // Need to use Graphics2D for rotation, not Graphics
+                       Graphics2D g2d = result.createGraphics();
+                       switch (inRotationDegrees)
+                       {
+                               case 90:
+                                       g2d.rotate(Math.PI / 2, 0.0, 0.0);
+                                       g2d.drawImage(inImage, 0, -scaledSize.width, scaledSize.height, scaledSize.width, null);
+                                       break;
+                               case 180:
+                                       g2d.rotate(Math.PI, scaledSize.width/2.0, scaledSize.height/2.0);
+                                       g2d.drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
+                                       break;
+                               case 270:
+                                       g2d.rotate(Math.PI * 3/2, 0.0, 0.0);
+                                       g2d.drawImage(inImage, -scaledSize.height, 0, scaledSize.height, scaledSize.width, null);
+                       }
+                       // Clear up memory
+                       g2d.dispose();
+               }
+               return result;
        }
 }