[lasem] svg_view: avoid cairo errors due to not invertible pattern matrix.

[Emmanuel Pacaud <emmanuel src gnome org>]

commit c6177203accded62272efc7eae99949a4a910f70
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Tue Jun 12 23:14:27 2012 +0200

    svg_view: avoid cairo errors due to not invertible pattern matrix.

 src/lsmsvgview.c                              |   10 +++
 tests/data/svg/misc/not-invertible-matrix.svg |   95 +++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 0 deletions(-)
---
diff --git a/src/lsmsvgview.c b/src/lsmsvgview.c
index 4acdc2a..09c2b44 100644
--- a/src/lsmsvgview.c
+++ b/src/lsmsvgview.c
@@ -262,6 +262,8 @@ lsm_svg_view_create_surface_pattern (LsmSvgView *view,
 	cairo_surface_t *surface;
 	cairo_pattern_t *pattern;
 	cairo_matrix_t matrix;
+	cairo_matrix_t inv_matrix;
+	cairo_status_t status;
 	double x1, y1, x2, y2;
 	double device_width, device_height;
 	double x_scale, y_scale;
@@ -332,6 +334,14 @@ lsm_svg_view_create_surface_pattern (LsmSvgView *view,
 		cairo_matrix_translate (&matrix, -viewport->x, -viewport->y);
 	}
 
+	inv_matrix = matrix;
+	status = cairo_matrix_invert (&inv_matrix);
+
+	if (status != CAIRO_STATUS_SUCCESS) {
+		lsm_debug_render ("[LsmSvgView::create_surface_pattern] Not invertible matrix");
+		return FALSE;
+	}
+
 	cairo_pattern_set_matrix (view->pattern_data->pattern, &matrix);
 	cairo_pattern_set_extend (view->pattern_data->pattern, CAIRO_EXTEND_REPEAT);
 
diff --git a/tests/data/svg/misc/not-invertible-matrix.svg b/tests/data/svg/misc/not-invertible-matrix.svg
new file mode 100755
index 0000000..7a2e77f
--- /dev/null
+++ b/tests/data/svg/misc/not-invertible-matrix.svg
@@ -0,0 +1,95 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1 Basic//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-basic.dtd";>  
+
+<!--======================================================================-->
+<!--=  Copyright 2000 World Wide Web Consortium, (Massachusetts          =-->
+<!--=  Institute of Technology, Institut National de Recherche en        =-->
+<!--=  Informatique et en Automatique, Keio University). All Rights      =-->
+<!--=  Reserved. See http://www.w3.org/Consortium/Legal/.                =-->
+<!--======================================================================-->
+<!-- =====================================================================-->
+<!--                                                                      -->
+<!-- gradPatt-transform-BE-09.svg                                         -->
+<!-- renamed for 1.1 suite to pservers-grad-06-b.svg	                  -->
+<!--                                                                      -->
+<!-- Test that the viewer can handle the gradientTransform and            -->
+<!-- the patternTransform attribute on gradients and patterns             -->
+<!-- respectively.                                                        -->
+<!--                                                                      -->
+<!-- Author : Haroon Sheikh  08-Mar-2000                                  -->
+<!-- Revised for 1.1 : Jun Fujisawa 19-Feb-2002                           -->
+<!--                                                                      -->
+<!-- History:                                                             -->
+<!--  09-Mar-2000, HSS: Serial#1 created.                                 -->
+<!--  02-Jun-2000,  DJ: Fixed gradientTransform to patternTransform.      -->
+<!--  03-Aug-2000, LH=" update DOCTYPE for CR DTD, 20000802" ser# .       -->
+<!--  16-Aug-2000, LH="rename" ser#3.                                     -->
+<!--                                                                      -->
+<!-- =====================================================================-->
+<!--======================================================================-->
+<!--= Note. After October 2000, revision history is kept as CVS 'commit' =-->
+<!--= log messages, and therefore is no longer in the preceding preamble.=-->
+<!--======================================================================-->
+<svg xmlns="http://www.w3.org/2000/svg"; xmlns:xlink="http://www.w3.org/1999/xlink"; id="svg-root" viewBox="0 0 480 360" width="100%" height="100%" version="1.1" baseProfile="basic">
+	<SVGTestCase xmlns="http://www.w3.org/2000/02/svg/testsuite/description/";>
+		<OperatorScript version="$Revision: 1.7 $" testname="pservers-grad-06-b.svg">
+			<Paragraph>
+				Test that the viewer can handle the gradientTransform and the patternTransform
+				attribute on gradients and patterns respectively.
+			</Paragraph>
+			<Paragraph>
+				From top-down the appearance of objects is as follows.
+			</Paragraph>
+			<Paragraph>
+				The top rectangle has a linear gradient whose coordinate system has been scaled down by
+				a half. So the gradient travelling from left to righ (from blue to red to lime) should 
+				only occuply the left half the rectangle.
+			</Paragraph>
+			<Paragraph>
+				The next rectangle has radial gradient that has been translated to the center and skewed
+				in the positive X direction by 45 degrees. Therefore the gradient should appear 
+				ellipltical and rotated around the center.
+			</Paragraph>
+			<Paragraph>
+				The last row contains a rectangle with pattern on the fill. The transformation on the 
+				pattern moves the coordinate system to the top left of the rectangle and then scales it 
+				by a factor of 2 and then skew's it in the X direction by 45 degrees. The pattern 
+				consists of a 2 by 2 array of colored rectangles.
+			</Paragraph>
+			<Paragraph>
+				The rendered picture should match the reference image exactly, except for possible
+				variations in the labelling text (per CSS2 rules).  
+			</Paragraph>
+		</OperatorScript>
+	</SVGTestCase>
+	<title id="test-title">pservers-grad-06-b</title>
+	<desc id="test-desc">Test that the viewer can handle the gradientTransform and the patternTransform attribute on gradients and patterns respectively.</desc>
+	<!--======================================================================-->
+	<!--Content of Test Case follows...                  =====================-->
+	<!--======================================================================-->
+	<g id="test-body-content">
+		<!-- ====================================================================== -->
+		<!-- Linear Gradient with gradientTransforms                                -->
+		<!-- ====================================================================== -->
+		<linearGradient id="Grad1" gradientUnits="userSpaceOnUse" x1="0" y1="0" x2="430" y2="0" gradientTransform="matrix (0 0 0 0 0 0)">
+			<stop stop-color="blue" offset="0"/>
+			<stop stop-color="red" offset="0.5"/>
+			<stop stop-color="lime" offset="1"/>
+		</linearGradient>
+		<rect x="20" y="20" width="440" height="50" fill="url(#Grad1)"/>
+		<text font-family="Arial" font-size="30" x="20" y="100">matrix(0 0 0 0 0 0) on gradient</text>
+		<!-- ====================================================================== -->
+		<!-- Pattern filled rectangles with a patternTransform.                     -->
+		<!-- ====================================================================== -->
+		<pattern patternUnits="userSpaceOnUse" id="Pat3" x="0" y="0" width="20" height="20" patternTransform="matrix(0 0 0 0 0 0)">
+			<rect x="0" y="0" width="10" height="10" fill="red"/>
+			<rect x="10" y="0" width="10" height="10" fill="green"/>
+			<rect x="0" y="10" width="10" height="10" fill="blue"/>
+			<rect x="10" y="10" width="10" height="10" fill="yellow"/>
+		</pattern>
+		<rect x="20" y="210" width="440" height="50" fill="url(#Pat3)"/>
+		<text font-family="Arial" font-size="30" x="20" y="290">matrix(0 0 0 0 0 0) on pattern</text>
+	</g>
+	<text id="revision" x="10" y="340" font-size="40" stroke="none" fill="black">$Revision: 1.7 $</text>
+	<rect id="test-frame" x="1" y="1" width="478" height="358" fill="none" stroke="#000000"/>
+</svg>