Add a BGR to RGBA twiddling JNI function

Change-Id: Iafa2c1805eea2f521479dc97d5668d82b1c91bef

android/Bootstrap/src/org/libreoffice/android/Bootstrap.java

@@ -39,6 +39,7 @@ import fi.iki.tml.CommandLine;
 
 import java.io.File;
 import java.io.InputStream;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Scanner;
 
@@ -108,6 +109,13 @@ public class Bootstrap extends NativeActivity
     // the Android logging mechanism, or stops the redirection.
     public static native boolean redirect_stdio(boolean state);
 
+    // The DIB returned by css.awt.XBitmap.getDIB is in BGR_888 form, at least
+    // for Writer documents. We need it in Android's Bitmap.Config.ARGB_888
+    // format, which actually is RGBA_888, whee... At least in Android 4.0.3,
+    // at least on my device. No idea if it is always like that or not, the
+    // documentation sucks.
+    public static native void twiddle_BGR_to_RGBA(byte[] source, int offset, int width, int height, ByteBuffer destination);
+
     // This setup() method is called 1) in apps that use *this* class as their activity from onCreate(),
     // and 2) should be called from other kinds of LO code using apps.
     public static void setup(Activity activity)

sal/android/lo-bootstrap.c

@@ -1861,6 +1861,50 @@ Java_org_libreoffice_android_Bootstrap_redirect_1stdio(JNIEnv* env,
     return current;
 }
 
+__attribute__ ((visibility("default")))
+void
+Java_org_libreoffice_android_Bootstrap_twiddle_1BGR_1to_1RGBA(JNIEnv* env,
+                                                              jobject clazz,
+                                                              jbyteArray source,
+                                                              jint offset,
+                                                              jint width,
+                                                              jint height,
+                                                              jobject destination)
+{
+    jbyte *dst = (jbyte*) (*env)->GetDirectBufferAddress(env, destination);
+    void *a = (*env)->GetPrimitiveArrayCritical(env, source, NULL);
+    jbyte *src = ((jbyte *) a) + offset;
+
+    jbyte *srcp;
+    jbyte *dstp = dst;
+    int step = ((((width * 3) - 1) / 4) + 1) * 4;
+
+    int i, j;
+
+    (void) clazz;
+
+    if (height > 0) {
+        srcp = src + step * (height - 1);
+        step = -step;
+    } else {
+        srcp = src;
+    }
+
+    LOGI("twiddle: src=%p, srcp=%p, dstp=%p, step=%d", src, srcp, dstp, step);
+
+    for (i = 0; i < height; i++) {
+        for (j = 0; j < width; j++) {
+            *dstp++ = srcp[j*3+2];
+            *dstp++ = srcp[j*3+1];
+            *dstp++ = srcp[j*3+0];
+            *dstp++ = 0xFF;
+        }
+        srcp += step;
+    }
+
+    (*env)->ReleasePrimitiveArrayCritical(env, source, a, 0);
+}
+
 __attribute__ ((visibility("default")))
 JavaVM *
 lo_get_javavm(void)