Render themes: PNG scaling, fix #595

docs/Changelog.md

@@ -3,6 +3,7 @@
 ## New since 0.10.0
 
 - Render themes: tag transform [#420](https://github.com/mapsforge/vtm/issues/420)
+- Render themes: PNG scaling [#595](https://github.com/mapsforge/vtm/issues/595)
 - PathLayer(s) scaled width [#594](https://github.com/mapsforge/vtm/issues/594)
 - vtm-models module [#580](https://github.com/mapsforge/vtm/issues/580)
 - Many other minor improvements and bug fixes

vtm-android/src/org/oscim/android/canvas/AndroidBitmap.java

@@ -1,7 +1,7 @@
 /*
  * Copyright 2013 Hannes Janetzek
  * Copyright 2016 Longri
- * Copyright 2016 devemux86
+ * Copyright 2016-2018 devemux86
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -23,6 +23,8 @@ import android.graphics.BitmapFactory;
 import android.opengl.GLES20;
 import android.opengl.GLUtils;
 
+import org.oscim.backend.CanvasAdapter;
+import org.oscim.utils.GraphicUtils;
 import org.oscim.utils.IOUtils;
 
 import java.io.ByteArrayOutputStream;
@@ -31,7 +33,7 @@ import java.io.InputStream;
 import static android.graphics.Bitmap.Config.ARGB_8888;
 
 public class AndroidBitmap implements org.oscim.backend.canvas.Bitmap {
-    final Bitmap mBitmap;
+    Bitmap mBitmap;
 
     public AndroidBitmap(InputStream inputStream) {
         Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
@@ -43,6 +45,12 @@ public class AndroidBitmap implements org.oscim.backend.canvas.Bitmap {
         mBitmap = bitmap;
     }
 
+    public AndroidBitmap(InputStream inputStream, int width, int height, int percent) {
+        this(inputStream);
+        float[] newSize = GraphicUtils.imageSize(getWidth(), getHeight(), CanvasAdapter.getScale(), width, height, percent);
+        scaleTo((int) newSize[0], (int) newSize[1]);
+    }
+
     @Override
     public boolean isValid() {
         return mBitmap != null;
@@ -117,4 +125,17 @@ public class AndroidBitmap implements org.oscim.backend.canvas.Bitmap {
             IOUtils.closeQuietly(outputStream);
         }
     }
+
+    @Override
+    public void scaleTo(int width, int height) {
+        if (getWidth() != width || getHeight() != height) {
+            // The effect of the filter argument to createScaledBitmap is not well documented in the
+            // official android docs, but according to
+            // http://stackoverflow.com/questions/2895065/what-does-the-filter-parameter-to-createscaledbitmap-do
+            // passing true results in smoother edges, less pixelation.
+            // If smoother corners improve the readability of map labels is perhaps debatable.
+            android.graphics.Bitmap scaledBitmap = android.graphics.Bitmap.createScaledBitmap(mBitmap, width, height, true);
+            mBitmap = scaledBitmap;
+        }
+    }
 }

vtm-android/src/org/oscim/android/canvas/AndroidGraphics.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2010, 2011, 2012 mapsforge.org
- * Copyright 2016-2017 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2017 Longri
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
@@ -58,6 +58,11 @@ public final class AndroidGraphics extends CanvasAdapter {
         return new AndroidBitmap(inputStream);
     }
 
+    @Override
+    public Bitmap decodeBitmapImpl(InputStream inputStream, int width, int height, int percent) {
+        return new AndroidBitmap(inputStream, width, height, percent);
+    }
+
     @Override
     public Bitmap decodeSvgBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException {
         return new AndroidSvgBitmap(inputStream, width, height, percent);

vtm-android/src/org/oscim/android/canvas/AndroidSvgBitmap.java

@@ -1,7 +1,7 @@
 /*
  * Copyright 2010, 2011, 2012 mapsforge.org
  * Copyright 2013-2014 Ludwig M Brinckmann
- * Copyright 2014-2017 devemux86
+ * Copyright 2014-2018 devemux86
  *
  * This program is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -24,6 +24,7 @@ import android.graphics.RectF;
 import com.caverock.androidsvg.SVG;
 
 import org.oscim.backend.CanvasAdapter;
+import org.oscim.utils.GraphicUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -41,34 +42,12 @@ public class AndroidSvgBitmap extends AndroidBitmap {
 
             double scale = scaleFactor / Math.sqrt((picture.getHeight() * picture.getWidth()) / defaultSize);
 
-            float bitmapWidth = (float) (picture.getWidth() * scale);
+            float[] bmpSize = GraphicUtils.imageSize(picture.getWidth(), picture.getHeight(), (float) scale, width, height, percent);
-            float bitmapHeight = (float) (picture.getHeight() * scale);
 
-            float aspectRatio = (1f * picture.getWidth()) / picture.getHeight();
+            android.graphics.Bitmap bitmap = android.graphics.Bitmap.createBitmap((int) Math.ceil(bmpSize[0]),
-
+                    (int) Math.ceil(bmpSize[1]), Bitmap.Config.ARGB_8888);
-            if (width != 0 && height != 0) {
-                // both width and height set, override any other setting
-                bitmapWidth = width;
-                bitmapHeight = height;
-            } else if (width == 0 && height != 0) {
-                // only width set, calculate from aspect ratio
-                bitmapWidth = height * aspectRatio;
-                bitmapHeight = height;
-            } else if (width != 0 && height == 0) {
-                // only height set, calculate from aspect ratio
-                bitmapHeight = width / aspectRatio;
-                bitmapWidth = width;
-            }
-
-            if (percent != 100) {
-                bitmapWidth *= percent / 100f;
-                bitmapHeight *= percent / 100f;
-            }
-
-            android.graphics.Bitmap bitmap = android.graphics.Bitmap.createBitmap((int) Math.ceil(bitmapWidth),
-                    (int) Math.ceil(bitmapHeight), Bitmap.Config.ARGB_8888);
             Canvas canvas = new Canvas(bitmap);
-            canvas.drawPicture(picture, new RectF(0, 0, bitmapWidth, bitmapHeight));
+            canvas.drawPicture(picture, new RectF(0, 0, bmpSize[0], bmpSize[1]));
 
             return bitmap;
         } catch (Exception e) {

vtm-desktop/src/org/oscim/awt/AwtBitmap.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016-2017 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2016-2017 Longri
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
@@ -21,13 +21,18 @@ package org.oscim.awt;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.utils.BufferUtils;
 
+import org.oscim.backend.CanvasAdapter;
 import org.oscim.backend.GL;
 import org.oscim.backend.canvas.Bitmap;
 import org.oscim.renderer.bucket.TextureBucket;
+import org.oscim.utils.GraphicUtils;
 import org.oscim.utils.IOUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.awt.AlphaComposite;
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -41,17 +46,10 @@ public class AwtBitmap implements Bitmap {
     private static final Logger log = LoggerFactory.getLogger(AwtBitmap.class);
 
     BufferedImage bitmap;
-    int width;
-    int height;
-
-    boolean internal;
 
     public AwtBitmap(int width, int height, int format) {
         bitmap = new BufferedImage(width, height, format != 0 ? format : BufferedImage.TYPE_INT_ARGB);
-        this.width = width;
-        this.height = height;
 
-        internal = true;
         // if (!this.bitmap.isAlphaPremultiplied())
         // this.bitmap.coerceData(true);
     }
@@ -59,17 +57,19 @@ public class AwtBitmap implements Bitmap {
     AwtBitmap(InputStream inputStream) throws IOException {
 
         this.bitmap = ImageIO.read(inputStream);
-        this.width = this.bitmap.getWidth();
-        this.height = this.bitmap.getHeight();
         if (!this.bitmap.isAlphaPremultiplied()
                 && this.bitmap.getType() == BufferedImage.TYPE_INT_ARGB)
             this.bitmap.coerceData(true);
     }
 
+    AwtBitmap(InputStream inputStream, int width, int height, int percent) throws IOException {
+        this(inputStream);
+        float[] newSize = GraphicUtils.imageSize(getWidth(), getHeight(), CanvasAdapter.getScale(), width, height, percent);
+        scaleTo((int) newSize[0], (int) newSize[1]);
+    }
+
     public AwtBitmap(BufferedImage bitmap) {
         this.bitmap = bitmap;
-        this.width = this.bitmap.getWidth();
-        this.height = this.bitmap.getHeight();
         if (!this.bitmap.isAlphaPremultiplied()
                 && this.bitmap.getType() == BufferedImage.TYPE_INT_ARGB)
             this.bitmap.coerceData(true);
@@ -77,12 +77,12 @@ public class AwtBitmap implements Bitmap {
 
     @Override
     public int getWidth() {
-        return width;
+        return bitmap.getWidth();
     }
 
     @Override
     public int getHeight() {
-        return height;
+        return bitmap.getHeight();
     }
 
     @Override
@@ -108,17 +108,17 @@ public class AwtBitmap implements Bitmap {
         int[] pixels;
         IntBuffer buffer;
 
-        if (width * height < TextureBucket.TEXTURE_HEIGHT * TextureBucket.TEXTURE_WIDTH) {
+        if (bitmap.getWidth() * bitmap.getHeight() < TextureBucket.TEXTURE_HEIGHT * TextureBucket.TEXTURE_WIDTH) {
             pixels = tmpPixel;
             buffer = tmpBuffer;
             buffer.clear();
         } else {
-            pixels = new int[width * height];
+            pixels = new int[bitmap.getWidth() * bitmap.getHeight()];
-            buffer = BufferUtils.newIntBuffer(width * height);
+            buffer = BufferUtils.newIntBuffer(bitmap.getWidth() * bitmap.getHeight());
         }
 
         // FIXME dont convert to argb when there data is greyscale
-        bitmap.getRGB(0, 0, width, height, pixels, 0, width);
+        bitmap.getRGB(0, 0, bitmap.getWidth(), bitmap.getHeight(), pixels, 0, bitmap.getWidth());
 
         if (WRITE_TEX) {
             try {
@@ -131,7 +131,7 @@ public class AwtBitmap implements Bitmap {
             }
         }
 
-        for (int i = 0, n = width * height; i < n; i++) {
+        for (int i = 0, n = bitmap.getWidth() * bitmap.getHeight(); i < n; i++) {
             int c = pixels[i];
             if (c == 0)
                 continue;
@@ -143,11 +143,11 @@ public class AwtBitmap implements Bitmap {
             pixels[i] = (c & 0xff000000) | r << 16 | g << 8 | b;
         }
 
-        buffer.put(pixels, 0, width * height);
+        buffer.put(pixels, 0, bitmap.getWidth() * bitmap.getHeight());
         buffer.flip();
 
-        Gdx.gl20.glTexImage2D(GL.TEXTURE_2D, 0, GL.RGBA, width,
+        Gdx.gl20.glTexImage2D(GL.TEXTURE_2D, 0, GL.RGBA, bitmap.getWidth(),
-                height, 0, GL.RGBA, GL.UNSIGNED_BYTE, buffer);
+                bitmap.getHeight(), 0, GL.RGBA, GL.UNSIGNED_BYTE, buffer);
     }
 
     @Override
@@ -173,4 +173,19 @@ public class AwtBitmap implements Bitmap {
         }
         return null;
     }
+
+    @Override
+    public void scaleTo(int width, int height) {
+        if (getWidth() != width || getHeight() != height) {
+            BufferedImage resizedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+            Graphics2D graphics = resizedImage.createGraphics();
+            graphics.setComposite(AlphaComposite.Src);
+            graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
+            graphics.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
+            graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+            graphics.drawImage(bitmap, 0, 0, width, height, null);
+            graphics.dispose();
+            bitmap = resizedImage;
+        }
+    }
 }

vtm-desktop/src/org/oscim/awt/AwtGraphics.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2017 Longri
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
@@ -108,6 +108,11 @@ public class AwtGraphics extends CanvasAdapter {
         return new AwtBitmap(inputStream);
     }
 
+    @Override
+    public Bitmap decodeBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException {
+        return new AwtBitmap(inputStream, width, height, percent);
+    }
+
     @Override
     public Bitmap decodeSvgBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException {
         return new AwtSvgBitmap(inputStream, width, height, percent);

vtm-desktop/src/org/oscim/awt/AwtSvgBitmap.java

@@ -19,6 +19,7 @@ import com.kitfox.svg.SVGDiagram;
 import com.kitfox.svg.app.beans.SVGIcon;
 
 import org.oscim.backend.CanvasAdapter;
+import org.oscim.utils.GraphicUtils;
 
 import java.awt.Dimension;
 import java.awt.image.BufferedImage;
@@ -39,34 +40,12 @@ public class AwtSvgBitmap extends AwtBitmap {
 
             double scale = scaleFactor / Math.sqrt((diagram.getHeight() * diagram.getWidth()) / defaultSize);
 
-            float bitmapWidth = (float) (diagram.getWidth() * scale);
+            float[] bmpSize = GraphicUtils.imageSize(diagram.getWidth(), diagram.getHeight(), (float) scale, width, height, percent);
-            float bitmapHeight = (float) (diagram.getHeight() * scale);
-
-            float aspectRatio = diagram.getWidth() / diagram.getHeight();
-
-            if (width != 0 && height != 0) {
-                // both width and height set, override any other setting
-                bitmapWidth = width;
-                bitmapHeight = height;
-            } else if (width == 0 && height != 0) {
-                // only width set, calculate from aspect ratio
-                bitmapWidth = height * aspectRatio;
-                bitmapHeight = height;
-            } else if (width != 0 && height == 0) {
-                // only height set, calculate from aspect ratio
-                bitmapHeight = width / aspectRatio;
-                bitmapWidth = width;
-            }
-
-            if (percent != 100) {
-                bitmapWidth *= percent / 100f;
-                bitmapHeight *= percent / 100f;
-            }
 
             SVGIcon icon = new SVGIcon();
             icon.setAntiAlias(true);
             icon.setAutosize(SVGIcon.AUTOSIZE_STRETCH);
-            icon.setPreferredSize(new Dimension((int) bitmapWidth, (int) bitmapHeight));
+            icon.setPreferredSize(new Dimension((int) bmpSize[0], (int) bmpSize[1]));
             icon.setSvgURI(uri);
             BufferedImage bufferedImage = new BufferedImage(icon.getIconWidth(), icon.getIconHeight(), BufferedImage.TYPE_INT_ARGB);
             icon.paintIcon(null, bufferedImage.createGraphics(), 0, 0);

vtm-ios/src/org/oscim/ios/backend/IosBitmap.java

@@ -1,5 +1,6 @@
 /*
  * Copyright 2016-2017 Longri
+ * Copyright 2018 devemux86
  *
  * This program is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -82,13 +83,25 @@ public class IosBitmap implements Bitmap {
         CGImage image = new UIImage(data).getCGImage();
         this.width = (int) image.getWidth();
         this.height = (int) image.getHeight();
-        this.cgBitmapContext = CGBitmapContext.create(width, height, 8, 4 * width,
+        this.cgBitmapContext = CGBitmapContext.create(this.width, this.height, 8, 4 * this.width,
                 CGColorSpace.createDeviceRGB(), CGImageAlphaInfo.PremultipliedLast);
 
-        this.cgBitmapContext.drawImage(new CGRect(0, 0, width, height), image);
+        this.cgBitmapContext.drawImage(new CGRect(0, 0, this.width, this.height), image);
         image.dispose();
     }
 
+    /**
+     * Constructor<br>
+     * Create a IosBitmap from given InputStream
+     *
+     * @param inputStream
+     * @throws IOException
+     */
+    public IosBitmap(InputStream inputStream, int width, int height, int percent) throws IOException {
+        // TODO Scaling
+        this(inputStream);
+    }
+
     /**
      * Constructor<br>
      * Load a IosBitmap from Asset with given FilePath
@@ -256,4 +269,9 @@ public class IosBitmap implements Bitmap {
         NSData data = uiImage.toPNGData();
         return data.getBytes();
     }
+
+    @Override
+    public void scaleTo(int width, int height) {
+        // TODO
+    }
 }

vtm-ios/src/org/oscim/ios/backend/IosGraphics.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2016 Longri
- * Copyright 2016 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2017 Longri
  *
  * This program is free software: you can redistribute it and/or modify it under the
@@ -59,6 +59,11 @@ public class IosGraphics extends CanvasAdapter {
         return new IosBitmap(inputStream);
     }
 
+    @Override
+    protected Bitmap decodeBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException {
+        return new IosBitmap(inputStream, width, height, percent);
+    }
+
     @Override
     protected Bitmap decodeSvgBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException {
         return new IosSvgBitmap(inputStream, width, height, percent);

vtm-ios/src/org/oscim/ios/backend/IosSvgBitmap.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2016 Longri
- * Copyright 2016-2017 devemux86
+ * Copyright 2016-2018 devemux86
  *
  * This program is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -16,6 +16,7 @@
 package org.oscim.ios.backend;
 
 import org.oscim.backend.CanvasAdapter;
+import org.oscim.utils.GraphicUtils;
 import org.oscim.utils.IOUtils;
 import org.robovm.apple.coregraphics.CGRect;
 import org.robovm.apple.coregraphics.CGSize;
@@ -62,31 +63,9 @@ public class IosSvgBitmap extends IosBitmap {
 
         double scale = scaleFactor / Math.sqrt((viewRect.getHeight() * viewRect.getWidth()) / defaultSize);
 
-        float bitmapWidth = (float) (viewRect.getWidth() * scale);
+        float[] bmpSize = GraphicUtils.imageSize((float) viewRect.getWidth(), (float) viewRect.getHeight(), (float) scale, width, height, percent);
-        float bitmapHeight = (float) (viewRect.getHeight() * scale);
 
-        float aspectRatio = (float) (viewRect.getWidth() / viewRect.getHeight());
+        return renderer.asImageWithSize(new CGSize(bmpSize[0], bmpSize[1]), 1);
-
-        if (width != 0 && height != 0) {
-            // both width and height set, override any other setting
-            bitmapWidth = width;
-            bitmapHeight = height;
-        } else if (width == 0 && height != 0) {
-            // only width set, calculate from aspect ratio
-            bitmapWidth = height * aspectRatio;
-            bitmapHeight = height;
-        } else if (width != 0 && height == 0) {
-            // only height set, calculate from aspect ratio
-            bitmapHeight = width / aspectRatio;
-            bitmapWidth = width;
-        }
-
-        if (percent != 100) {
-            bitmapWidth *= percent / 100f;
-            bitmapHeight *= percent / 100f;
-        }
-
-        return renderer.asImageWithSize(new CGSize(bitmapWidth, bitmapHeight), 1);
     }
 
     private static UIImage getResourceBitmapImpl(InputStream inputStream, int width, int height, int percent) {

vtm-web/src/org/oscim/gdx/client/GwtBitmap.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016 devemux86
+ * Copyright 2016-2018 devemux86
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -105,4 +105,9 @@ public class GwtBitmap implements Bitmap {
         // TODO
         return null;
     }
+
+    @Override
+    public void scaleTo(int width, int height) {
+        // TODO
+    }
 }

vtm-web/src/org/oscim/gdx/client/GwtGdxGraphics.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2017 Longri
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
@@ -55,6 +55,12 @@ public class GwtGdxGraphics extends CanvasAdapter {
         return null;
     }
 
+    @Override
+    public Bitmap decodeBitmapImpl(InputStream inputStream, int width, int height, int percent) {
+        // TODO
+        return null;
+    }
+
     @Override
     public Bitmap decodeSvgBitmapImpl(InputStream inputStream, int width, int height, int percent) {
         // TODO

vtm/src/org/oscim/backend/CanvasAdapter.java

@@ -113,10 +113,25 @@ public abstract class CanvasAdapter {
      */
     protected abstract Bitmap decodeBitmapImpl(InputStream inputStream) throws IOException;
 
+    /**
+     * Create {@link Bitmap} from InputStream.
+     *
+     * @param inputStream the input stream
+     * @param width       requested width (0: no change)
+     * @param height      requested height (0: no change)
+     * @param percent     requested scale percent (100: no change)
+     * @return the bitmap
+     */
+    protected abstract Bitmap decodeBitmapImpl(InputStream inputStream, int width, int height, int percent) throws IOException;
+
     public static Bitmap decodeBitmap(InputStream inputStream) throws IOException {
         return g.decodeBitmapImpl(inputStream);
     }
 
+    public static Bitmap decodeBitmap(InputStream inputStream, int width, int height, int percent) throws IOException {
+        return g.decodeBitmapImpl(inputStream, width, height, percent);
+    }
+
     /**
      * Create SVG {@link Bitmap} from InputStream.
      *
@@ -182,7 +197,7 @@ public abstract class CanvasAdapter {
         if (src.toLowerCase(Locale.ENGLISH).endsWith(".svg"))
             bitmap = decodeSvgBitmap(inputStream, width, height, percent);
         else
-            bitmap = decodeBitmap(inputStream);
+            bitmap = decodeBitmap(inputStream, width, height, percent);
         inputStream.close();
         return bitmap;
     }

vtm/src/org/oscim/backend/canvas/Bitmap.java

@@ -1,6 +1,7 @@
 /*
  * Copyright 2013 Hannes Janetzek
  * Copyright 2016 Longri
+ * Copyright 2018 devemux86
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -65,4 +66,6 @@ public interface Bitmap {
     boolean isValid();
 
     byte[] getPngEncodedData();
+
+    void scaleTo(int width, int height);
 }

vtm/src/org/oscim/utils/GraphicUtils.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2018 devemux86
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.utils;
+
+/**
+ * Utility class for graphics operations.
+ */
+public final class GraphicUtils {
+
+    /**
+     * Given the original image size, as well as width, height, percent parameters,
+     * can compute the final image size.
+     *
+     * @param picWidth    original image width
+     * @param picHeight   original image height
+     * @param scaleFactor scale factor to screen DPI
+     * @param width       requested width (0: no change)
+     * @param height      requested height (0: no change)
+     * @param percent     requested scale percent (100: no change)
+     */
+    public static float[] imageSize(float picWidth, float picHeight, float scaleFactor, int width, int height, int percent) {
+        float bitmapWidth = picWidth * scaleFactor;
+        float bitmapHeight = picHeight * scaleFactor;
+
+        float aspectRatio = picWidth / picHeight;
+
+        if (width != 0 && height != 0) {
+            // both width and height set, override any other setting
+            bitmapWidth = width;
+            bitmapHeight = height;
+        } else if (width == 0 && height != 0) {
+            // only width set, calculate from aspect ratio
+            bitmapWidth = height * aspectRatio;
+            bitmapHeight = height;
+        } else if (width != 0 && height == 0) {
+            // only height set, calculate from aspect ratio
+            bitmapHeight = width / aspectRatio;
+            bitmapWidth = width;
+        }
+
+        if (percent != 100) {
+            bitmapWidth *= percent / 100f;
+            bitmapHeight *= percent / 100f;
+        }
+
+        return new float[]{bitmapWidth, bitmapHeight};
+    }
+
+    private GraphicUtils() {
+    }
+}