Change desktop coordinate system to match SVG (LP #170049)

Fixed bugs:
  - https://launchpad.net/bugs/170049

(bzr r9288)

2 files changed, 4 insertions, 19 deletions

diff --git a/src/helper/pixbuf-ops.cpp b/src/helper/pixbuf-ops.cpp
index 3be63aa68..c26d55b8b 100644
--- a/src/helper/pixbuf-ops.cpp
+++ b/src/helper/pixbuf-ops.cpp
@@ -113,7 +113,7 @@ sp_generate_internal_bitmap(SPDocument *doc, gchar const */*filename*/,
      double padding = 1.0;
 
      Geom::Point origin(screen.min()[Geom::X],
-                      sp_document_height(doc) - screen[Geom::Y].extent() - screen.min()[Geom::Y]);
+                        screen.min()[Geom::Y]);
 
      origin[Geom::X] = origin[Geom::X] + (screen[Geom::X].extent() * ((1 - padding) / 2));
      origin[Geom::Y] = origin[Geom::Y] + (screen[Geom::Y].extent() * ((1 - padding) / 2));
diff --git a/src/helper/png-write.cpp b/src/helper/png-write.cpp
index b1c135db0..8eb9e27bf 100644
--- a/src/helper/png-write.cpp
+++ b/src/helper/png-write.cpp
@@ -424,24 +424,9 @@ sp_export_png_file(SPDocument *doc, gchar const *filename,
 
     sp_document_ensure_up_to_date(doc);
 
-    /* Calculate translation by transforming to document coordinates (flipping Y)*/
-    Geom::Point translation = Geom::Point(-area[Geom::X][0], area[Geom::Y][1] - sp_document_height(doc));
-
-    /*  This calculation is only valid when assumed that (x0,y0)= area.corner(0) and (x1,y1) = area.corner(2)
-     * 1) a[0] * x0 + a[2] * y1 + a[4] = 0.0
-     * 2) a[1] * x0 + a[3] * y1 + a[5] = 0.0
-     * 3) a[0] * x1 + a[2] * y1 + a[4] = width
-     * 4) a[1] * x0 + a[3] * y0 + a[5] = height
-     * 5) a[1] = 0.0;
-     * 6) a[2] = 0.0;
-     *
-     * (1,3) a[0] * x1 - a[0] * x0 = width
-     * a[0] = width / (x1 - x0)
-     * (2,4) a[3] * y0 - a[3] * y1 = height
-     * a[3] = height / (y0 - y1)
-     * (1) a[4] = -a[0] * x0
-     * (2) a[5] = -a[3] * y1
-     */
+    /* Calculate translation */
+    Geom::Point translation = Geom::Point(-area[Geom::X][0], -area[Geom::Y][0]);
+
 
     Geom::Matrix const affine(Geom::Translate(translation)
                             * Geom::Scale(width / area.width(),