Enable multi-touch emulation with -gpu on

This CL implements a callback that gets invoked by OpenGLES emulator on it framebuffer
updates. This allows transferring framebuffer changes to the supporting device.

Proper implementation of this new callback also required changes to JPEG compression,
addressing:

1. OpenGLES framebuffer format is RGBA8889, which required implementing line conversion
   for this format.
2. OpenGLES framebuffer is (or at least could be) bottom-up arranged. This requires changes
   to the compressor, so it compresses the FB starting from the bottom, so the resulting
   image is up-bottom.

Change-Id: Icd4efbe4a251c838adfa3518decbfc43a7ef06c8

2 files changed, 54 insertions, 0 deletions

diff --git a/distrib/jpeg-6b/jccolor.c b/distrib/jpeg-6b/jccolor.c
index 67078ab..61e262d 100644
--- a/distrib/jpeg-6b/jccolor.c
+++ b/distrib/jpeg-6b/jccolor.c
@@ -219,6 +219,52 @@ rgb565_ycc_convert (j_compress_ptr cinfo,
     }
   }
 }
+
+/* Converts RGBA8888 row into YCbCr */
+METHODDEF(void)
+rgba8888_ycc_convert (j_compress_ptr cinfo,
+		 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+		 JDIMENSION output_row, int num_rows)
+{
+  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+  register int r, g, b;
+  register INT32 * ctab = cconvert->rgb_ycc_tab;
+  register INT32* inptr;
+  register JSAMPROW outptr0, outptr1, outptr2;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+
+  while (--num_rows >= 0) {
+    inptr = (INT32*)(*input_buf++);
+    outptr0 = output_buf[0][output_row];
+    outptr1 = output_buf[1][output_row];
+    outptr2 = output_buf[2][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      register const unsigned char* color = (unsigned char*)(inptr + col);
+      r = (*color) & 0xff; color++;
+      g = (*color) & 0xff; color++;
+      b = (*color) & 0xff; color++;
+      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
+       * must be too; we do not need an explicit range-limiting operation.
+       * Hence the value being shifted is never negative, and we don't
+       * need the general RIGHT_SHIFT macro.
+       */
+      /* Y */
+      outptr0[col] = (JSAMPLE)
+		((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+		 >> SCALEBITS);
+      /* Cb */
+      outptr1[col] = (JSAMPLE)
+		((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+		 >> SCALEBITS);
+      /* Cr */
+      outptr2[col] = (JSAMPLE)
+		((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+		 >> SCALEBITS);
+    }
+  }
+}
 #endif  /* ANDROID_RGB */
 
 /**************** Cases other than RGB -> YCbCr **************/
@@ -505,6 +551,10 @@ jinit_color_converter (j_compress_ptr cinfo)
     if (cinfo->input_components != 2)
       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
     break;
+  case JCS_RGBA_8888:
+    if (cinfo->input_components != 4)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
 #endif  /* ANDROID_RGB */
 
   default:			/* JCS_UNKNOWN can be anything */
@@ -551,6 +601,9 @@ jinit_color_converter (j_compress_ptr cinfo)
     else if (cinfo->in_color_space == JCS_RGB_565) {
       cconvert->pub.start_pass = rgb_ycc_start;
       cconvert->pub.color_convert = rgb565_ycc_convert;
+    } else if (cinfo->in_color_space == JCS_RGBA_8888) {
+      cconvert->pub.start_pass = rgb_ycc_start;
+      cconvert->pub.color_convert = rgba8888_ycc_convert;
     }
 #endif  /* ANDROID_RGB */
     else
diff --git a/distrib/jpeg-6b/jcparam.c b/distrib/jpeg-6b/jcparam.c
index b305179..f8404dd 100644
--- a/distrib/jpeg-6b/jcparam.c
+++ b/distrib/jpeg-6b/jcparam.c
@@ -379,6 +379,7 @@ jpeg_default_colorspace (j_compress_ptr cinfo)
     break;
 #ifdef ANDROID_RGB
   case JCS_RGB_565:
+  case JCS_RGBA_8888:
     jpeg_set_colorspace(cinfo, JCS_YCbCr);
     break;
 #endif  /* ANDROID_RGB */