[gs-cvs] rev 8275 - trunk/gs/src

[ken at ghostscript.com]

Author: ken
Date: 2007-10-09 01:28:49 -0700 (Tue, 09 Oct 2007)
New Revision: 8275

Modified:
   trunk/gs/src/gdevpdfi.c
   trunk/gs/src/gdevpsdi.c
Log:
pdfwrite: Allow downsampling of images in a /Indexed colour space, provided the
downsampling type is 'subsample'.

DETAILS:
Bug 689265 "PDF created by GS 8.57 is much larger than from competitive creator"

The original job contains several images, including one large one, which are in a 
/Indexed colour space. We can't use average or bicubic downsampling with /Indexed
colour space, because the colours in the space may not be linear. It ought to be
possible to use subsampling though.

Where we previously checked the image colour space and decided to disable downsampling
if the colour space was /Indexed, we now additionally check the downsampling type
and permit it if the type is 'Subsample'.

(gdevpdfi.c) pdf_begin_typed_image, check the downsample type as well as the colour 
space before deciding not to allow downsampling. 

(gdevpdsi.c) psdf_setup_image_filters, check if the colour space is /Indexed before 
deciding which set of image parameters to use (2 places). Also, if we do encounter a
/Indexed space, make the compression filter into Flate to ensure we don't try and use any 
kind of JPEG compression, which may not work properly with Indexed spaces, and in any case
is not the most appropriate type of compression in this situation.

EXPECTED DIFFERENCES:
None


Modified: trunk/gs/src/gdevpdfi.c
===================================================================
--- trunk/gs/src/gdevpdfi.c	2007-10-09 00:06:24 UTC (rev 8274)
+++ trunk/gs/src/gdevpdfi.c	2007-10-09 08:28:49 UTC (rev 8275)
@@ -631,7 +631,8 @@
 				    (pim->Width <= 64 && pim->Height <= 64) ||
 				    pdev->transfer_not_identity ? 1 : 2);
     if (image[0].pixel.ColorSpace != NULL &&
-	image[0].pixel.ColorSpace->type->index == gs_color_space_index_Indexed)
+	image[0].pixel.ColorSpace->type->index == gs_color_space_index_Indexed 
+	&& pdev->params.ColorImage.DownsampleType != ds_Subsample)
 	pie->writer.alt_writer_count = 1;
     image[1] = image[0];
     names = (in_line ? &pdf_color_space_names_short : &pdf_color_space_names);

Modified: trunk/gs/src/gdevpsdi.c
===================================================================
--- trunk/gs/src/gdevpsdi.c	2007-10-09 00:06:24 UTC (rev 8274)
+++ trunk/gs/src/gdevpsdi.c	2007-10-09 08:28:49 UTC (rev 8275)
@@ -525,16 +525,23 @@
 	ncomp = 1;
     } else {
 	ncomp = gs_color_space_num_components(pim->ColorSpace);
-	if (ncomp == 1) {
-	    if (bpc == 1)
-		params = pdev->params.MonoImage;
-	    else
-		params = pdev->params.GrayImage;
-	    if (params.Depth == -1)
-		params.Depth = bpc;
+	if (pim->ColorSpace->type->index == gs_color_space_index_Indexed) {
+	    params = pdev->params.ColorImage;
+	    /* Ensure we don't use JPEG on a /Indexed colour space */
+	    params.AutoFilter = false;
+	    params.Filter = "FlateEncode";
 	} else {
-	    params = pdev->params.ColorImage;
+	    if (ncomp == 1) {
+		if (bpc == 1)
+		    params = pdev->params.MonoImage;
+    		else
+		    params = pdev->params.GrayImage;
+		if (params.Depth == -1)
+		    params.Depth = bpc;
+	    } else {
+		params = pdev->params.ColorImage;
 	    /* params.Depth is reset below */
+	    }
 	}
     }
 
@@ -556,7 +563,7 @@
 	resolution = 1.0 / hypot(pt.x / pdev->HWResolution[0],
 				 pt.y / pdev->HWResolution[1]);
     }
-    if (ncomp == 1) {
+    if (ncomp == 1 && pim->ColorSpace && pim->ColorSpace->type->index != gs_color_space_index_Indexed) {
 	/* Monochrome, gray, or mask */
 	/* Check for downsampling. */
 	if (do_downsample(&params, pim, resolution)) {