changes scaler lib imgscalr with thumbnailator resulting in better images

updates to v0.9.2
update readme

Author: patrickfav

README.md

@@ -4,7 +4,7 @@ This is a powerful little tool that helps **converting single or batches of imag
 versions given the source scale factor or target width/height in [dp](http://developer.android.com/guide/practices/screens_support.html#density-independence).
 It has a **graphical** and **command line** interface and supports a wide array of image types for reading and conversion
 including PNG, JPEG, SVG, PSD and Android 9-patches. Using sophisticated scaling algorithms, it is designed to make conversion of images easy and
-fast while keeping the image quality high. To further optimize the output post processors like **pngcrush** and **mozJpeg** can be used (see section below).
+fast while keeping the image quality high (comparable to PS). To further optimize the output post processors like **pngcrush** and **mozJpeg** can be used (see section below).
 
 Usage:
 
@@ -56,8 +56,8 @@ Full list of arguments:
     -androidIncludeLdpiTvdpi              Android only: creates mipmap sub-folders instead of drawable.
     -androidMipmapInsteadOfDrawable       Android only: If set will include additional densities (ldpi and
                                           tvdpi)
-    -antiAliasing                         Anti-aliases images creating a little more blurred result; useful
-                                          for very small images
+    -antiAliasing                         Anti-aliases images creating a little more blurred result; a light
+                                          3x3 convolve matrix is used; useful for very small images
     -clean                                Deletes all file and folders in out dir that would be used in
                                           current configuration before converting.
     -compressionQuality <0.0-1.0>         Only used with compression 'jpg' sets the quality [0-1.0] where 1.0
@@ -192,12 +192,16 @@ If an image will be re-compressed with a file type that does not support alpha,
 
 ## Quality Comparison
 One of the main features of this converter is downscaling. Unfortunately without using specific algorithms, down scaled
- images may look jagged. Density converter uses the algorithms of [imgscalr](https://github.com/thebuzzmedia/imgscalr) which
- provide fairly good quality, comparable to Photoshop output (although PS comes out ahead a bit). The following
- diagram is to compare the expected quality when using this tool in comparison to Java's native Graphics2D and Photoshop.
+ images may look jagged. Density converter uses the algorithms of [Thumbnailator](https://github.com/coobird/thumbnailator) which
+ provide fairly good quality, comparable to Photoshop output. Thumbnailator turned out to generater better results than the other popular open source resizer lib [imgscalr](https://github.com/thebuzzmedia/imgscalr) which was used in previous versions. The following diagram is to compare the expected quality when using this tool in comparison to Java's native Graphics2D and Photoshop.
 
+![comparison-ldpi](src/main/resources/img/ldpi_comparison.png)
+![comparison-ldpi](src/main/resources/img/mdpi_comparison.png)
 
-![comparison](src/main/resources/img/quality_comparison.png)
+1) Density Converter using Thumbnailator with default settings
+2) Photoshop CS5 with bicubic algorithm
+3) imgscalr with ULTRA_QUALITY setting
+4) Java2d with render hints VALUE_INTERPOLATION_BICUBIC, VALUE_RENDER_QUALITY, VALUE_ANTIALIAS_ON
 
 ## Post Processors
 
@@ -266,7 +270,7 @@ The .jar file will be in the generated `/target` folder
 ## Credits
 
 * TIFF, PSD, SVG image type support [TwelveMonkeys](https://github.com/haraldk/TwelveMonkeys)
-* HQ image resizing with [imgscalr](https://github.com/thebuzzmedia/imgscalr)
+* HQ image resizing with [Thumbnailator](https://github.com/coobird/thumbnailator)
 * JavaFx theme based on Flatter by [hendrikebbers](https://github.com/guigarage/javafx-collection/tree/master/flatter)
 * Image file icon: Icon made by [Freepik](http://www.freepik.com/)
 * 9-patch resizing routine from [Redwarp](https://github.com/redwarp/9-Patch-Resizer)

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>at.favre.tools</groupId>
     <artifactId>dconvert</artifactId>
-    <version>0.9.1</version>
+    <version>0.9.2</version>
 
     <prerequisites>
         <maven>3.1.0</maven>
@@ -85,9 +85,9 @@
         </dependency>
         <!-- hq image scaling -->
         <dependency>
-            <groupId>org.imgscalr</groupId>
-            <artifactId>imgscalr-lib</artifactId>
-            <version>4.2</version>
+            <groupId>net.coobird</groupId>
+            <artifactId>thumbnailator</artifactId>
+            <version>[0.4, 0.5)</version>
         </dependency>
         <!-- supported reading/writing image types -->
         <dependency>

src/main/java/at/favre/tools/dconvert/util/ImageUtil.java

@@ -24,7 +24,9 @@
 import com.twelvemonkeys.imageio.metadata.jpeg.JPEG;
 import com.twelvemonkeys.imageio.metadata.jpeg.JPEGSegment;
 import com.twelvemonkeys.imageio.metadata.jpeg.JPEGSegmentUtil;
-import org.imgscalr.Scalr;
+import net.coobird.thumbnailator.makers.FixedSizeThumbnailMaker;
+import net.coobird.thumbnailator.resizers.DefaultResizerFactory;
+import net.coobird.thumbnailator.resizers.Resizer;
 
 import javax.imageio.*;
 import javax.imageio.metadata.IIOMetadata;
@@ -34,7 +36,8 @@
 import javax.imageio.stream.ImageOutputStream;
 import java.awt.*;
 import java.awt.image.BufferedImage;
-import java.awt.image.BufferedImageOp;
+import java.awt.image.ConvolveOp;
+import java.awt.image.Kernel;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -46,6 +49,9 @@
  * Main Util class containing all
  */
 public class ImageUtil {
+    public static final ConvolveOp OP_ANTIALIAS = new ConvolveOp(
+            new Kernel(3, 3, new float[]{.0f, .08f, .0f, .08f, .68f, .08f,
+                    .0f, .08f, .0f}), ConvolveOp.EDGE_NO_OP, null);
 
     public static LoadedImage loadImage(File input) throws Exception {
         if (input == null) {
@@ -172,14 +178,17 @@ public static BufferedImage scale(BufferedImage imageToScale, int dWidth, int dH
         BufferedImage scaledImage = null;
         if (imageToScale != null) {
 
-            BufferedImageOp[] bufferedImageOpArray = new BufferedImageOp[]{};
+            Resizer resizer = DefaultResizerFactory.getInstance()
+                    .getResizer(new Dimension(imageToScale.getWidth(), imageToScale.getHeight()), new Dimension(dWidth, dHeight));
+
+            scaledImage = new FixedSizeThumbnailMaker(dWidth, dHeight, false, true)
+                    .resizer(resizer)
+                    .make(imageToScale);
 
             if (antiAlias) {
-                bufferedImageOpArray = new BufferedImageOp[]{Scalr.OP_ANTIALIAS};
+                scaledImage = OP_ANTIALIAS.filter(scaledImage, null);
             }
 
-            scaledImage = Scalr.resize(imageToScale, Scalr.Method.ULTRA_QUALITY, Scalr.Mode.FIT_EXACT, dWidth, dHeight, bufferedImageOpArray);
-
             if (!compression.hasTransparency) {
                 BufferedImage convertedImg = new BufferedImage(scaledImage.getWidth(), scaledImage.getHeight(), BufferedImage.TYPE_INT_RGB);
                 convertedImg.getGraphics().drawImage(scaledImage, 0, 0, background, null);

src/main/resources/bundles/strings.properties

@@ -64,7 +64,7 @@ arg.descr.cmd.verbose=If set will log to console more verbose
 arg.descr.dryrun=Will not create any images or folder. Useful as fast preview in log what images in what resolutions would be created.
 arg.descr.halterror=If set will stop the process if an error occurred during conversion
 arg.descr.androidldpi=Android only: If set will include additional densities (ldpi and tvdpi)
-arg.descr.antialiasing=Anti-aliases images creating a little more blurred result; useful for very small images
+arg.descr.antialiasing=Anti-aliases images creating a little more blurred result; a light 3x3 convolve matrix is used; useful for very small images
 arg.descr.androidmipmap=Android only: creates mipmap sub-folders instead of drawable.
 arg.descr.pngcrush=Will post-process all pngs with pngcrush, a lossless compressor. The executable must be set in the system PATH as 'pngcrush' i.e executable from every path. Pngcrush is a tool to compress pngs. Requires v1.7.22+
 arg.descr.webp=Will additionally convert all png/gif to lossless wepb and all jpg to lossy webp with cwebp. Does not delete source files. The executable must be set in the system path as 'cwebp' i.e executable from every path. cwebp is the official converter from Google.

src/main/resources/img/ldpi_comparison.png

@@ -34,7 +34,7 @@ public class GUITest extends ApplicationTest {
 
 	@BeforeClass
 	public static void setupSpec() throws Exception {
-		if (false) {
+		if (true) {
 			System.setProperty("testfx.robot", "glass");
 			System.setProperty("testfx.headless", "true");
 			System.setProperty("prism.order", "sw");