[Plplot-cvs] SF.net SVN: plplot:[11197] trunk/examples/python

[<hba...@us...>]

Revision: 11197
          http://plplot.svn.sourceforge.net/plplot/?rev=11197&view=rev
Author:   hbabcock
Date:     2010-09-22 14:28:41 +0000 (Wed, 22 Sep 2010)

Log Message:
-----------
Add a python example of how to use memcairo with and without alpha values.

Modified Paths:
--------------
    trunk/examples/python/CMakeLists.txt

Added Paths:
-----------
    trunk/examples/python/test_memcairo.py

Modified: trunk/examples/python/CMakeLists.txt
===================================================================
--- trunk/examples/python/CMakeLists.txt	2010-09-22 14:14:07 UTC (rev 11196)
+++ trunk/examples/python/CMakeLists.txt	2010-09-22 14:28:41 UTC (rev 11197)
@@ -87,6 +87,7 @@
   test_type1.py
   test_hebrew_diacritic.py
   test_mem.py
+  test_memcairo.py
   )
 
 if(ENABLE_tk)

Added: trunk/examples/python/test_memcairo.py
===================================================================
--- trunk/examples/python/test_memcairo.py	                        (rev 0)
+++ trunk/examples/python/test_memcairo.py	2010-09-22 14:28:41 UTC (rev 11197)
@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+
+#  Copyright (C) 2010 Simon Wood
+
+#  Simple demo of plsmem, plsmema and the memcairo device under Python.
+#
+#  This file is part of PLplot.
+#
+#  PLplot is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Library Public License as published
+#  by the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  PLplot is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU Library General Public License for more details.
+#
+#  You should have received a copy of the GNU Library General Public License
+#  along with PLplot; if not, write to the Free Software
+#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+#
+
+import Image
+import math
+import numpy.numarray
+
+from plplot_python_start import *
+
+from plplot import *
+
+# ---------------------------------------------------
+# Build random array (aka fake data)
+
+plseed(1234)
+x=[]
+y=[]
+
+for i in range(500) :
+    x.append(plrandd() * 360)
+    y.append(plrandd() * 90)
+
+# compute binned density on 15' boundaries
+# 360' gives 24 divisions
+# 90' gives 6 divisions
+
+width = 24
+height = 6
+
+max_val = 0
+data = numpy.numarray.zeros((width,height))
+
+for i in range(len(x)):
+    data[int(x[i]/(360/width))][int(y[i]/(90/height))] += 1
+    if data[int(x[i]/(360/width))][int(y[i]/(90/height))] > max_val:
+        max_val +=1
+
+# ---------------------------------------------------
+# Initialise buffer
+
+# Start from a blank canvas
+width = 480
+height = 320
+my_buffer = numpy.numarray.zeros((height,width,3), numpy.uint8)
+my_buffer_alpha = numpy.numarray.zeros((height,width,4), numpy.uint8)
+
+'''
+# Or open an existing image
+# (note 'asarray' will fail as it sees PIL image as an array already and 
+# does not perform a copy to make a writable array)
+src_img = Image.open("input.png")
+my_buffer = numpy.array(src_img.convert('RGB'), numpy.uint8)
+(width, height) = src_img.size
+'''
+
+# ---------------------------------------------------
+# Rectangular plot w/o alpha values
+
+# initialise for mem driver
+plsmem(width,height,my_buffer)
+plstart ("memcairo", 1, 1);
+
+plcol0(1)
+plenv(0, 360, 0, 90, 0, 2)
+plcol0(2)
+pllab("Azimuth", "Elevation", "Rectangular Sky View")
+
+# plot binned density
+plimage(data, 0, 360, 0, 90, 0, max_val, 0, 360, 0, 90)
+
+# plot points
+plpoin(x,y,5)
+
+# have to finish plotting so that the plot data gets
+# transferred back from the cairo working surface
+# to the user supplied memory.
+plend1()
+
+# Use fromstring as frombuffer will invert the image
+my_image = Image.fromstring("RGB", (width,height), my_buffer)
+my_image.save('memcairo_RGB.png')
+
+
+# ---------------------------------------------------
+# Rectangular plot with alpha values
+
+# initialise for mem driver
+plsmema(width,height,my_buffer_alpha)
+plstart ("memcairo", 1, 1);
+
+plcol0(1)
+plenv(0, 360, 0, 90, 0, 2)
+plcol0(2)
+pllab("Azimuth", "Elevation", "Rectangular Sky View")
+
+# plot binned density
+plimage(data, 0, 360, 0, 90, 0, max_val, 0, 360, 0, 90)
+
+# plot points
+plpoin(x,y,5)
+
+# have to finish plotting so that the plot data gets
+# transferred back from the cairo working surface
+# to the user supplied memory.
+plend()
+
+# Use fromstring as frombuffer will invert the image
+my_image = Image.fromstring("RGBA", (width,height), my_buffer_alpha)
+my_image.save('memcairo_RGBA.png')


Property changes on: trunk/examples/python/test_memcairo.py
___________________________________________________________________
Added: svn:executable
   + *


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