[Plplot-cvs] SF.net SVN: plplot:[8845] trunk/drivers/cairo.c

[<ai...@us...>]

Revision: 8845
          http://plplot.svn.sourceforge.net/plplot/?rev=8845&view=rev
Author:   airwin
Date:     2008-10-01 06:17:49 +0000 (Wed, 01 Oct 2008)

Log Message:
-----------
Document what the surface dimension units are in each device case. Sometimes
they are pixels, sometimes they are points (1/72th of an inch), and 
sometimes (memcairo) the maximum surface dimension is defined by the size of
the buffer so the unit would be buffer pixels (as opposed to screen
resolution pixels).  This documentation is the first step in understanding the
sizes of the cairo results for the various cairo devices.

Modified Paths:
--------------
    trunk/drivers/cairo.c

Modified: trunk/drivers/cairo.c
===================================================================
--- trunk/drivers/cairo.c	2008-10-01 06:07:51 UTC (rev 8844)
+++ trunk/drivers/cairo.c	2008-10-01 06:17:49 UTC (rev 8845)
@@ -890,6 +890,7 @@
 
   /* Create an cairo surface & context that are associated with the X window. */
   defaultVisual = DefaultVisual(aStream->XDisplay, 0);
+  /* Dimension units are pixels from cairo documentation. */
   aStream->cairoSurface = cairo_xlib_surface_create(aStream->XDisplay, aStream->XWindow, defaultVisual, pls->xlength, pls->ylength);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 
@@ -1213,6 +1214,7 @@
   plOpenFile(pls);
 
   /* Create an cairo surface & context for PDF file. */
+  /* Dimension units are pts = 1/72 inches from cairo documentation. */
   aStream->cairoSurface = cairo_pdf_surface_create_for_stream((cairo_write_func_t)write_to_stream, pls->OutFile, (double)pls->xlength, (double)pls->ylength);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 
@@ -1284,6 +1286,7 @@
   plOpenFile(pls);
 
   /* Create an cairo surface & context for PS file. */
+  /* Dimension units are pts = 1/72 inches from cairo documentation. */
   aStream->cairoSurface = cairo_ps_surface_create_for_stream((cairo_write_func_t)write_to_stream, pls->OutFile, (double)pls->ylength, (double)pls->xlength);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 
@@ -1378,6 +1381,7 @@
   pls->dev = aStream;
 
   /* Create an cairo surface & context for SVG file. */
+  /* Dimension units are pts = 1/72 inches from cairo documentation. */
   aStream->cairoSurface = cairo_svg_surface_create_for_stream((cairo_write_func_t)write_to_stream, pls->OutFile, (double)pls->xlength, (double)pls->ylength);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 
@@ -1468,6 +1472,7 @@
   pls->dev = aStream;
 
   /* Create a new cairo surface & context for PNG file. */
+  /* Dimension units are pixels from cairo documentation. */
   aStream->cairoSurface = cairo_image_surface_create(CAIRO_FORMAT_RGB24, (double)pls->xlength, (double)pls->ylength);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 
@@ -1623,6 +1628,8 @@
 
   /* Create a Cairo drawing surface from the input data */
   aStream->cairoSurface = 
+  /* Dimension units are width, height of buffer image from cairo 
+     documentation. */
     cairo_image_surface_create_for_data (aStream->cairo_format_memory, CAIRO_FORMAT_RGB24, pls->xlength, pls->ylength, stride);
   aStream->cairoContext = cairo_create(aStream->cairoSurface);
 


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