PS/PDF: Set image Interpolation flag

If the filter mode is anything other than DEFAILT, FAST or NEAREST set the
Interpolate flag in the image dictionary so that a smoothing filter is
applied when rasterising the vector file.

As we have no control over the implementation of the Interpolate filter
(the PS/PDF specifications leave it undefined) we need to capture the
output of poppler/GS and update our reference images. (For a couple of
tests, the filtering is irrelevant so for those we set the filter to
NEAREST.)

Note that GhostScript's Interpolate filter does not work on rotated images
(and a variety of other transformations) so several of the PS reference
images have use nearest-neighbour sampling instead of a bilinear filter.

src/cairo-pdf-surface.c

@@ -1411,9 +1411,10 @@ _cairo_pdf_surface_emit_smask (cairo_pdf_surface_t	*surface,
 /* Emit image data into the given surface, providing a resource that
  * can be used to reference the data in image_ret. */
 static cairo_status_t
-_cairo_pdf_surface_emit_image (cairo_pdf_surface_t   *surface,
-                               cairo_image_surface_t *image,
-                               cairo_pdf_resource_t  *image_ret)
+_cairo_pdf_surface_emit_image (cairo_pdf_surface_t     *surface,
+                               cairo_image_surface_t   *image,
+                               cairo_pdf_resource_t    *image_ret,
+			       cairo_filter_t           filter)
 {
     cairo_status_t status = CAIRO_STATUS_SUCCESS;
     char *rgb;
@@ -1422,6 +1423,7 @@ _cairo_pdf_surface_emit_image (cairo_pdf_surface_t   *surface,
     int i, x, y;
     cairo_pdf_resource_t smask = {0}; /* squelch bogus compiler warning */
     cairo_bool_t need_smask;
+    const char *interpolate;
 
     /* These are the only image formats we currently support, (which
      * makes things a lot simpler here). This is enforced through
@@ -1486,11 +1488,25 @@ _cairo_pdf_surface_emit_image (cairo_pdf_surface_t   *surface,
 	    need_smask = TRUE;
     }
 
+    switch (filter) {
+    case CAIRO_FILTER_GOOD:
+    case CAIRO_FILTER_BEST:
+    case CAIRO_FILTER_BILINEAR:
+	interpolate = "true";
+	break;
+    case CAIRO_FILTER_FAST:
+    case CAIRO_FILTER_NEAREST:
+    case CAIRO_FILTER_GAUSSIAN:
+	interpolate = "false";
+	break;
+    }
+
 #define IMAGE_DICTIONARY	"   /Type /XObject\n"		\
 				"   /Subtype /Image\n"	\
 				"   /Width %d\n"		\
 				"   /Height %d\n"		\
 				"   /ColorSpace /DeviceRGB\n"	\
+	                        "   /Interpolate %s\n" \
 				"   /BitsPerComponent 8\n"
 
     if (need_smask)
@@ -1500,13 +1516,15 @@ _cairo_pdf_surface_emit_image (cairo_pdf_surface_t   *surface,
 						 IMAGE_DICTIONARY
 						 "   /SMask %d 0 R\n",
 						 image->width, image->height,
+						 interpolate,
 						 smask.id);
     else
 	status = _cairo_pdf_surface_open_stream (surface,
 						 NULL,
 						 TRUE,
 						 IMAGE_DICTIONARY,
-						 image->width, image->height);
+						 image->width, image->height,
+						 interpolate);
     if (status)
 	goto CLEANUP_RGB;
 
@@ -1537,7 +1555,7 @@ _cairo_pdf_surface_emit_image_surface (cairo_pdf_surface_t     *surface,
     if (status)
 	goto BAIL;
 
-    status = _cairo_pdf_surface_emit_image (surface, image, resource);
+    status = _cairo_pdf_surface_emit_image (surface, image, resource, pattern->base.filter);
     if (status)
 	goto BAIL;
 

src/cairo-ps-surface.c

@@ -1863,7 +1863,8 @@ _cairo_ps_surface_emit_base85_string (cairo_ps_surface_t    *surface,
 static cairo_status_t
 _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
 			      cairo_image_surface_t *image,
-			      cairo_operator_t	     op)
+			      cairo_operator_t	     op,
+			      cairo_filter_t         filter)
 {
     cairo_status_t status;
     unsigned char *data, *data_compressed;
@@ -1874,10 +1875,24 @@ _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
     cairo_bool_t use_mask;
     uint32_t *pixel;
     int bit;
+    const char *interpolate;
 
     if (image->base.status)
 	return image->base.status;
 
+    switch (filter) {
+    case CAIRO_FILTER_GOOD:
+    case CAIRO_FILTER_BEST:
+    case CAIRO_FILTER_BILINEAR:
+	interpolate = "true";
+	break;
+    case CAIRO_FILTER_FAST:
+    case CAIRO_FILTER_NEAREST:
+    case CAIRO_FILTER_GAUSSIAN:
+	interpolate = "false";
+	break;
+    }
+
     transparency = _cairo_image_analyze_transparency (image);
 
     /* PostScript can not represent the alpha channel, so we blend the
@@ -1998,10 +2013,12 @@ _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
 				     "    /ImageType 1 def\n"
 				     "    /Width %d def\n"
 				     "    /Height %d def\n"
+				     "    /Interpolate %s def\n"
 				     "    /BitsPerComponent 8 def\n"
 				     "    /Decode [ 0 1 0 1 0 1 ] def\n",
 				     image->width,
-				     image->height);
+				     image->height,
+				     interpolate);
 
 	if (surface->use_string_datasource) {
 	    _cairo_output_stream_printf (surface->stream,
@@ -2024,6 +2041,7 @@ _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
 				     "    /ImageType 1 def\n"
 				     "    /Width %d def\n"
 				     "    /Height %d def\n"
+				     "    /Interpolate %s def\n"
 				     "    /BitsPerComponent 1 def\n"
 				     "    /Decode [ 1 0 ] def\n"
 				     "    /ImageMatrix [ 1 0 0 -1 0 %d ] def\n"
@@ -2033,6 +2051,7 @@ _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
 				     image->height,
 				     image->width,
 				     image->height,
+				     interpolate,
 				     image->height);
     } else {
 	_cairo_output_stream_printf (surface->stream,
@@ -2059,9 +2078,11 @@ _cairo_ps_surface_emit_image (cairo_ps_surface_t    *surface,
 	}
 
 	_cairo_output_stream_printf (surface->stream,
+				     "  /Interpolate %s def\n"
 				     "  /ImageMatrix [ 1 0 0 -1 0 %d ] def\n"
 				     "end\n"
 				     "image\n",
+				     interpolate,
 				     opaque_image->height);
     }
 
@@ -2246,7 +2267,8 @@ _cairo_ps_surface_emit_surface (cairo_ps_surface_t      *surface,
 	status = _cairo_ps_surface_emit_meta_surface (surface,
 						      meta_surface);
     } else {
-	status = _cairo_ps_surface_emit_image (surface, surface->image, op);
+	status = _cairo_ps_surface_emit_image (surface, surface->image,
+					       op, pattern->base.filter);
     }
 
     return status;

test/Makefile.am

@@ -359,8 +359,14 @@ REFERENCE_IMAGES = \
 	close-path-ps2-ref.png	\
 	close-path-ps3-ref.png	\
 	composite-integer-translate-over-ref.png	\
+	composite-integer-translate-over-ps2-ref.png	\
+	composite-integer-translate-over-ps3-ref.png	\
 	composite-integer-translate-over-repeat-ref.png	\
+	composite-integer-translate-over-repeat-ps2-ref.png	\
+	composite-integer-translate-over-repeat-ps3-ref.png	\
 	composite-integer-translate-source-ref.png	\
+	composite-integer-translate-source-ps2-ref.png	\
+	composite-integer-translate-source-ps3-ref.png	\
 	copy-path-ps2-ref.png	\
 	copy-path-ps3-ref.png	\
 	copy-path-ref.png	\
@@ -432,7 +438,11 @@ REFERENCE_IMAGES = \
 	extend-reflect-ps2-ref.png \
 	extend-reflect-ps3-ref.png \
 	extend-repeat-ref.png	\
+	extend-repeat-ps2-ref.png	\
+	extend-repeat-ps3-ref.png	\
 	extend-repeat-similar-ref.png	\
+	extend-repeat-similar-ps2-ref.png	\
+	extend-repeat-similar-ps3-ref.png	\
 	fallback-resolution-ppi37.5x37.5-ref.png \
 	fallback-resolution-ppi37.5x72-ref.png \
 	fallback-resolution-ppi37.5x75-ref.png \
@@ -584,6 +594,8 @@ REFERENCE_IMAGES = \
 	huge-pattern-pdf-ref.png	\
 	huge-pattern-pdf-rgb24-ref.png	\
 	image-surface-source-ref.png \
+	image-surface-source-ps2-ref.png \
+	image-surface-source-ps3-ref.png \
 	infinite-join-ref.png	\
 	infinite-join-ps2-ref.png	\
 	infinite-join-ps3-ref.png	\
@@ -869,18 +881,20 @@ REFERENCE_IMAGES = \
 	stroke-ctm-caps-ps2-ref.png \
 	stroke-ctm-caps-ps3-ref.png \
 	surface-pattern-big-scale-down-ref.png	\
-	surface-pattern-pdf-argb32-ref.png	\
-	surface-pattern-ps2-argb32-ref.png	\
-	surface-pattern-ps3-argb32-ref.png	\
+	surface-pattern-pdf-ref.png	\
+	surface-pattern-ps2-ref.png	\
+	surface-pattern-ps3-ref.png	\
 	surface-pattern-ref.png	\
-	surface-pattern-scale-down-pdf-argb32-ref.png	\
-	surface-pattern-scale-down-ps2-argb32-ref.png	\
-	surface-pattern-scale-down-ps3-argb32-ref.png	\
+	surface-pattern-scale-down-pdf-argb24-ref.png	\
+	surface-pattern-scale-down-pdf-rgb24-ref.png	\
+	surface-pattern-scale-down-ps2-ref.png	\
+	surface-pattern-scale-down-ps3-ref.png	\
 	surface-pattern-scale-down-ref.png	\
 	surface-pattern-scale-down-quartz-ref.png	\
 	surface-pattern-scale-up-pdf-argb32-ref.png	\
-	surface-pattern-scale-up-ps2-argb32-ref.png	\
-	surface-pattern-scale-up-ps3-argb32-ref.png	\
+	surface-pattern-scale-up-pdf-rgb24-ref.png	\
+	surface-pattern-scale-up-ps2-ref.png	\
+	surface-pattern-scale-up-ps3-ref.png	\
 	surface-pattern-scale-up-ref.png	\
 	surface-pattern-svg12-ref.png	\
 	surface-pattern-svg11-ref.png	\
@@ -964,6 +978,8 @@ REFERENCE_IMAGES = \
 	unbounded-operator-quartz-rgb24-ref.png	\
 	xlib-expose-event-ref.png \
 	xlib-surface-source-ref.png \
+	xlib-surface-source-ps2-ref.png \
+	xlib-surface-source-ps3-ref.png \
 	zero-alpha-ref.png
 
 EXTRA_DIST +=		\
@@ -1023,10 +1039,7 @@ $(REFERENCE_IMAGES)
 #                         on cairo_traps_t after strokes.
 #                         Test case should also be expanded to hit special-case
 #                         tessellators as well.
-# surface-pattern*      - old bugs in pixman, but fails PS/PDF due to lack of
-#                         /Interpolate support - which causes a half-pixel
-#                         shift in GS (and consequently virtually every
-#                         image/fallback-image using test to FAIL).
+# surface-pattern-big...- Strange, unexplained results for SVG/PS.
 XFAIL_TESTS =					\
 alpha-similar$(EXEEXT)				\
 big-line$(EXEEXT)				\
@@ -1039,10 +1052,7 @@ fallback-resolution$(EXEEXT)			\
 long-lines$(EXEEXT)				\
 self-copy-overlap$(EXEEXT)			\
 self-intersecting$(EXEEXT)			\
-surface-pattern$(EXEEXT)			\
 surface-pattern-big-scale-down$(EXEEXT)		\
-surface-pattern-scale-down$(EXEEXT)		\
-surface-pattern-scale-up$(EXEEXT)		\
 $(NULL)
 
 # Any test that doesn't generate a log file goes here
@@ -1289,7 +1299,6 @@ check-ref-dups:
 check-ref-missing:
 	@cd "$(srcdir)"; \
 	REFS=`git ls-files "*-ref.png"`; \
-	test x = "x$$REFS" && REFS=`ls *-ref.png`; \
 	ret=true; \
 	missing=""; \
 	for i in $$REFS; do \
@@ -1302,6 +1311,19 @@ check-ref-missing:
 		echo "Missing: $$missing"; \
 		ret=false; \
 	fi >&2; \
+	if $$ret; then \
+	    REFS=`ls *-ref.png`; \
+	    for i in $$REFS; do \
+		echo "" $(REFERENCE_IMAGES) "" | grep -sq " $$i " || missing="$$missing $$i" ; \
+	    done ; \
+	    if test -n "$$missing"; then \
+		    echo "*** Error: Sanity check failed"; \
+		    echo "Some local reference files are not included in the distribution or been added to git."; \
+		    echo "You probably need to add these to git and Makefile.am's REFERENCE_IMAGES."; \
+		    echo "Missing: $$missing"; \
+		    ret=false; \
+	    fi >&2; \
+	fi >&2; \
 	missing=""; \
 	for i in $(REFERENCE_IMAGES); do \
 	    echo "" $$REFS "" | grep -sq " $$i " || missing="$$missing $$i" ; \

test/bilevel-image.c

@@ -54,6 +54,7 @@ draw (cairo_t *cr, int width, int height)
 						CAIRO_FORMAT_ARGB32, 12, 4, 48);
 
     cairo_set_source_surface (cr, mask, 0, 0);
+    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);
     cairo_surface_destroy (mask);
 
     cairo_paint (cr);

test/create-from-png-stream.c

@@ -88,6 +88,7 @@ draw (cairo_t *cr, int width, int height)
     free (filename);
 
     cairo_set_source_surface (cr, surface, 0, 0);
+    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);
     cairo_paint (cr);
 
     cairo_surface_destroy (surface);

test/create-from-png.c

@@ -72,6 +72,7 @@ draw (cairo_t *cr, int width, int height)
     free (filename);
 
     cairo_set_source_surface (cr, surface, 0, 0);
+    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);
     cairo_paint (cr);
 
     cairo_surface_destroy (surface);

test/surface-pattern-scale-down.c

@@ -34,8 +34,7 @@ static cairo_test_draw_function_t draw;
 
 static const cairo_test_t test = {
     "surface-pattern-scale-down",
-    "Test scaled-down transformed not-repeated surface patterns"
-    "\nFails xlib backend (with argb32) with inexplicable alpha in result",
+    "Test scaled-down transformed not-repeated surface patterns",
     SIZE, SIZE,
     draw
 };

test/surface-pattern-scale-up.c

@@ -24,6 +24,9 @@
  * Author: Behdad Esfahbod <behdad@behdad.org>
  */
 
+/* Exhibits nasty behaviour with GS due as their /Interpolate implementation
+ * does not function for rotated images. */
+
 #include <math.h>
 #include "cairo-test.h"
 #include <stdio.h>
@@ -34,8 +37,7 @@ static cairo_test_draw_function_t draw;
 
 static const cairo_test_t test = {
     "surface-pattern-scale-up",
-    "Test scaled-up transformed not-repeated surface patterns"
-    "\nFails xlib backend (with argb32) with inexplicable alpha in result",
+    "Test scaled-up transformed not-repeated surface patterns",
     SIZE, SIZE,
     draw
 };

test/surface-pattern.c

@@ -30,12 +30,14 @@
 
 #define SIZE 140
 
+/* Not GhostScript does not support /Interpolate on rotated images, so the PS
+ * output looks terrible, but is a known issue. */
+
 static cairo_test_draw_function_t draw;
 
 static const cairo_test_t test = {
     "surface-pattern",
-    "Test transformed repeated surface patterns"
-    "\nExhibiting a strange (very minor) failure in ps backend with device-offset",
+    "Test transformed repeated surface patterns",
     SIZE, SIZE,
     draw
 };