Projects / PNGwriter


The PNGwriter library, which requires libpng, allows you to plot to a 48-bit PNG file, saving it directly to disk. Plotting is as easy as specifying the red, green, and blue values and the x, y coordinates of the pixel. It includes functions for plotting simple geometric shapes (circle, rect, line), plotting text (UTF-8 support for Asian languages), reading the colour of a pixel, reading in a whole PNG file (great for image analysis), plotting and reading in HSV colourspace, and many others that might come in handy.

Operating Systems

Recent releases

  •  11 Feb 2009 08:54

    Release Notes: filegamma_ was corrected from 0.5 in one constructor to 0.6 as in all others. PNGwriter now handles a much greater range of input files with readfromfile(). In general, the alpha channel is discarded gracefully. Some issues remain: a PNG with information in the chroma chunk will not be read too accurately, and a PNG with a transparency chunk will be read incorrectly, though silently. Compiler warnings in drawtriangle() and drawbottom() were fixed.

    •  25 Jan 2005 23:11

      Release Notes: This release adds a function that returns the calculated width of a string of text if it were plotted, as well as four new figures: arrow, diamond, cross, and Maltese cross.

      •  11 Jan 2005 05:35

        Release Notes: The license was changed to an unmodified GNU General Public License.

        •  05 Jan 2005 06:48

          Release Notes: The documentation covering the compilation and installation process has been improved, and the installed README file now reflects the actual locations of installed files, not just the default locations. Also, the Makefile has been made more suitable for packaging.

          •  23 Oct 2004 14:33

            Release Notes: This version adds a function for fast plotting of triangles, fixes a serious bug in readfromfile() affecting versions compiled on Windows, and adds another example to the included pngtest program.


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