Expose TurboJPEG scaling features in Java wrapper

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@375 632fc199-4ca6-4c93-a231-07263d6284db

java/TJExample.java

@@ -38,13 +38,33 @@ public class TJExample {
 
   public static final String classname=new TJExample().getClass().getName();
 
+  private static void usage() {
+    System.out.println("\nUSAGE: java "+classname+" <Input file> <Output file> [options]\n");
+    System.out.println("Options:\n");
+    System.out.println("-scale 1/N = scale the width/height of the output image by a factor of 1/N");
+    System.out.println("             (N = 1, 2, 4, or 8}\n");
+    System.exit(1);
+  }
+
   public static void main(String argv[]) {
 
     try {
 
       if(argv.length<2) {
-        System.out.println("USAGE: java "+classname+" <Input file> <Output file>");
+        usage();
-        System.exit(1);
+      }
+
+      int scalefactor=1;
+      if(argv.length>2) {
+        for(int i=2; i<argv.length; i++) {
+          if(argv[i].equalsIgnoreCase("-scale") && i<argv.length-1) {
+            String [] scalearg=argv[++i].split("/");      
+            if(scalearg.length!=2 || Integer.parseInt(scalearg[0])!=1
+              || (scalefactor=Integer.parseInt(scalearg[1]))<1
+              || scalefactor>8 || (scalefactor&(scalefactor-1))!=0)
+              usage();
+          }
+        }
       }
 
       File file=new File(argv[0]);
@@ -68,9 +88,18 @@ public class TJExample {
         case TJ.GRAYSCALE:  System.out.println("Grayscale");  break;
         default:  System.out.println("Unknown subsampling");  break;
       }
+
+      if(scalefactor!=1) {
+        tji.width=(tji.width+scalefactor-1)/scalefactor;
+        tji.height=(tji.height+scalefactor-1)/scalefactor;
+        System.out.println("Dest. Image:  "+tji.width+" x "+tji.height
+          +" pixels");
+      }
+
+
       byte [] tmpbuf=new byte[tji.width*tji.height*3];
-      tjd.decompress(inputbuf, inputsize, tmpbuf, tji.width, tji.width*3,
+      tjd.decompress(inputbuf, inputsize, tmpbuf, tji.width*3,
-        tji.height, 3, TJ.BOTTOMUP);
+        3, 1, scalefactor, TJ.BOTTOMUP);
       tjd.close();
 
       TJCompressor tjc=new TJCompressor();

java/org/libjpegturbo/turbojpeg/TJDecompressor.java

@@ -56,7 +56,7 @@ public class TJDecompressor {
     throws Exception;
 
   public native void decompress(byte [] srcbuf, long size, byte [] dstbuf,
-    int width, int pitch, int height, int pixelsize, int flags)
+    int pitch, int pixelsize, int scale_num, int scale_denom, int flags)
     throws Exception;
 
   static {

turbojpeg-jni.c

@@ -169,7 +169,7 @@ JNIEXPORT jobject JNICALL Java_org_libjpegturbo_turbojpeg_TJDecompressor_decompr
 
 JNIEXPORT void JNICALL Java_org_libjpegturbo_turbojpeg_TJDecompressor_decompress
 	(JNIEnv *env, jobject obj, jbyteArray src, jlong size, jbyteArray dst,
-		jint width, jint pitch, jint height, jint pixelsize, jint flags)
+		jint pitch, jint pixelsize, jint scale_num, jint scale_denom, jint flags)
 {
 	tjhandle handle=0;
 	unsigned char *srcbuf=NULL, *dstbuf=NULL;
@@ -179,8 +179,8 @@ JNIEXPORT void JNICALL Java_org_libjpegturbo_turbojpeg_TJDecompressor_decompress
 	bailif0(srcbuf=(*env)->GetPrimitiveArrayCritical(env, src, 0));
 	bailif0(dstbuf=(*env)->GetPrimitiveArrayCritical(env, dst, 0));
 
-	if(tjDecompress(handle, srcbuf, (unsigned long)size, dstbuf, width, pitch,
+	if(tjDecompress2(handle, srcbuf, (unsigned long)size, dstbuf, pitch,
-		height, pixelsize, flags)==-1)
+		pixelsize, scale_num, scale_denom, flags)==-1)
 	{
 		(*env)->ReleasePrimitiveArrayCritical(env, dst, dstbuf, 0);
 		(*env)->ReleasePrimitiveArrayCritical(env, src, srcbuf, 0);

turbojpeg-mapfile.jni

@@ -7,6 +7,7 @@
 		tjDecompressHeader;
 		tjDecompressHeader2;
 		tjDecompress;
+		tjDecompress2;
 		tjDestroy;
 		tjGetErrorStr;
 		Java_org_libjpegturbo_turbojpeg_TJ_bufSize;