[dia] Taking another stab at bug 147386 - clipped PNG

[Hans Breuer <hans src gnome org>]

commit af9e49e5cbce7c5706f318a4cd1da3292da0f0cf
Author: Hans Breuer <hans breuer org>
Date:   Sat May 14 21:32:36 2011 +0200

    Taking another stab at bug 147386 - clipped PNG
    
    To ensure no clipping at top/left we need some extra gymnastics,
    otherwise a box with a line width one one pixel might loose the
    top/left border as in bug #147386
    
    Also some ceil for width and height when sizing the PNG surface.

 plug-ins/cairo/diacairo-renderer.c |    9 ++++++++-
 plug-ins/cairo/diacairo.c          |   13 ++++++-------
 2 files changed, 14 insertions(+), 8 deletions(-)
---
diff --git a/plug-ins/cairo/diacairo-renderer.c b/plug-ins/cairo/diacairo-renderer.c
index 6db8fa2..8de2785 100644
--- a/plug-ins/cairo/diacairo-renderer.c
+++ b/plug-ins/cairo/diacairo-renderer.c
@@ -74,6 +74,8 @@
 
 #include "diacairo.h"
 
+static void ensure_minimum_one_device_unit(DiaCairoRenderer *renderer, real *value);
+
 /* 
  * render functions 
  */ 
@@ -81,6 +83,7 @@ static void
 begin_render(DiaRenderer *self)
 {
   DiaCairoRenderer *renderer = DIA_CAIRO_RENDERER (self);
+  real onedu = 0.0;
 
   if (renderer->surface)
     renderer->cr = cairo_create (renderer->surface);
@@ -88,7 +91,11 @@ begin_render(DiaRenderer *self)
     g_assert (renderer->cr);
 
   cairo_scale (renderer->cr, renderer->scale, renderer->scale);
-  cairo_translate (renderer->cr, -renderer->dia->extents.left, -renderer->dia->extents.top);
+  /* to ensure no clipping at top/left we need some extra gymnastics,
+   * otherwise a box with a line witdh one one pixel might loose the
+   * top/left border as in bug #147386 */
+  ensure_minimum_one_device_unit (renderer, &onedu);
+  cairo_translate (renderer->cr, -renderer->dia->extents.left + onedu, -renderer->dia->extents.top + onedu);
   /* no more blurred UML diagrams */
   cairo_set_antialias (renderer->cr, CAIRO_ANTIALIAS_NONE);
 
diff --git a/plug-ins/cairo/diacairo.c b/plug-ins/cairo/diacairo.c
index 5b28cec..83d5c10 100644
--- a/plug-ins/cairo/diacairo.c
+++ b/plug-ins/cairo/diacairo.c
@@ -160,9 +160,8 @@ export_data(DiagramData *data, const gchar *filename,
   case OUTPUT_PNG :
     /* quite arbitrary, but consistent with ../pixbuf ;-) */
     renderer->scale = 20.0 * data->paper.scaling; 
-    width  = (data->extents.right - data->extents.left) * renderer->scale + 0.5;
-    height = (data->extents.bottom - data->extents.top) * renderer->scale + 0.5;
-
+    width  = ceil((data->extents.right - data->extents.left) * renderer->scale) + 1;
+    height = ceil((data->extents.bottom - data->extents.top) * renderer->scale) + 1;
     DIAG_NOTE(g_message ("PNG Surface %dx%d\n", (int)width, (int)height));
     /* use case screwed by API shakeup. We need to special case */
     renderer->surface = cairo_image_surface_create(
@@ -190,8 +189,8 @@ export_data(DiagramData *data, const gchar *filename,
   case OUTPUT_SVG :
     /* quite arbitrary, but consistent with ../pixbuf ;-) */
     renderer->scale = 20.0 * data->paper.scaling; 
-    width  = (data->extents.right - data->extents.left) * renderer->scale + 0.5;
-    height = (data->extents.bottom - data->extents.top) * renderer->scale + 0.5;
+    width  = ceil((data->extents.right - data->extents.left) * renderer->scale) + 1;
+    height = ceil((data->extents.bottom - data->extents.top) * renderer->scale) + 1;
     DIAG_NOTE(g_message ("SVG Surface %dx%d\n", (int)width, (int)height));
     /* use case screwed by API shakeup. We need to special case */
     renderer->surface = cairo_svg_surface_create(
@@ -245,8 +244,8 @@ export_data(DiagramData *data, const gchar *filename,
   default :
     /* quite arbitrary, but consistent with ../pixbuf ;-) */
     renderer->scale = 20.0 * data->paper.scaling; 
-    width  = (data->extents.right - data->extents.left) * renderer->scale;
-    height = (data->extents.bottom - data->extents.top) * renderer->scale;
+    width  = ceil((data->extents.right - data->extents.left) * renderer->scale) + 1;
+    height = ceil((data->extents.bottom - data->extents.top) * renderer->scale) + 1;
     DIAG_NOTE(g_message ("Image Surface %dx%d\n", (int)width, (int)height)); 
     renderer->surface = cairo_image_surface_create (CAIRO_FORMAT_A8, (int)width, (int)height);
   }