From 5ba95b7e1287ade0b8a1acf2f5cb73fa1f44c451 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 4 Nov 2008 09:22:28 +0000
Subject: [PATCH] [trace] Convert [1 0 0 1 0 0] to identity

Simplify the trace/replay by replacing the identity array with the
identity operator.
---
 util/cairo-trace/trace.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/util/cairo-trace/trace.c b/util/cairo-trace/trace.c
index 864038d4a..eeca07a13 100644
--- a/util/cairo-trace/trace.c
+++ b/util/cairo-trace/trace.c
@@ -800,6 +800,14 @@ _get_surface_id (cairo_surface_t *surface)
     return _get_id (SURFACE, surface);
 }
 
+static bool
+_matrix_is_identity (const cairo_matrix_t *m)
+{
+    return m->xx == 1. && m->yx == 0. &&
+	   m->xy == 0. && m->yy == 1. &&
+	   m->x0 == 0. && m->y0 == 0.;
+}
+
 #define BUFFER_SIZE 16384
 struct _data_stream {
     z_stream zlib_stream;
@@ -1558,10 +1566,14 @@ cairo_transform (cairo_t *cr, const cairo_matrix_t *matrix)
 void
 cairo_set_matrix (cairo_t *cr, const cairo_matrix_t *matrix)
 {
-    _emit_cairo_op (cr, "[%g %g %g %g %g %g] set_matrix\n",
-		    matrix->xx, matrix->yx,
-		    matrix->xy, matrix->yy,
-		    matrix->x0, matrix->y0);
+    if (_matrix_is_identity (matrix)) {
+	_emit_cairo_op (cr, "identity set_matrix\n");
+    } else {
+	_emit_cairo_op (cr, "[%g %g %g %g %g %g] set_matrix\n",
+			matrix->xx, matrix->yx,
+			matrix->xy, matrix->yy,
+			matrix->x0, matrix->y0);
+    }
     return DLCALL (cairo_set_matrix, cr, matrix);
 }
 
@@ -2707,11 +2719,15 @@ cairo_pattern_add_color_stop_rgba (cairo_pattern_t *pattern, double offset, doub
 void
 cairo_pattern_set_matrix (cairo_pattern_t *pattern, const cairo_matrix_t *matrix)
 {
-    _emit_pattern_op (pattern,
-		      "[%g %g %g %g %g %g] set_matrix\n",
-		      matrix->xx, matrix->yx,
-		      matrix->xy, matrix->yy,
-		      matrix->x0, matrix->y0);
+    if (_matrix_is_identity (matrix)) {
+	_emit_pattern_op (pattern, "identity set_matrix\n");
+    } else {
+	_emit_pattern_op (pattern,
+			  "[%g %g %g %g %g %g] set_matrix\n",
+			  matrix->xx, matrix->yx,
+			  matrix->xy, matrix->yy,
+			  matrix->x0, matrix->y0);
+    }
     return DLCALL (cairo_pattern_set_matrix, pattern, matrix);
 }