|  | # SDL_gfx Library ### SDL graphics drawing primitives and other support functions The SDL_gfx library evolved out of the SDL_gfxPrimitives code which provided basic drawing routines such as lines, circles or polygons and SDL_rotozoom which implemented a interpolating rotozoomer for SDL surfaces. The current components of the SDL_gfx library are: Graphic Primitives (SDL_gfxPrimitves.h) Rotozoomer (SDL_rotozoom.h) Framerate control (SDL_framerate.h) MMX image filters (SDL_imageFilter.h) The library is backwards compatible to the above mentioned code. Its is written in plain C and can be used in C++ code. (c) A. Schiffler, 1999-2003, licensed under the LGPL ### Screenshots
SDL_gfxPrimitives | SDL_rotozoom
### Downloads SDL_gfx-2.0.13.tar.gz SDL_gfx-2.0.13-1.src.rpm SDL_gfx-2.0.13-1.i586.rpm SDL_gfx-devel-2.0.13-1.i586.rpm SDL_gfx-demos-2.0.13-1.i586.rpm ### Supported Platforms The library compiles and is tested for a Linux target (gcc compiler) and a Win32 target (VisualC, xmingw32 cross-compiler) as well as BeOS and MacOS X PowerBuilder See README for VC and PowerBuilder compile information. When using the cross-compiler (available on the author's homepage), the build process generates .DLLs. You can use the command line 'LIB.EXE' tool to generate VC6 compatible .LIB files for linking purposes. ### Notes on Graphics Primitives Care has been taken so that all routines are fully alpha-aware and can blend any primitive onto the target surface if ALPHA<255. Surface depths supported are 1,2,3 and 4 bytes per pixel. Surface locking is implemented in each routine and the library should work well with hardware accelerated surfaces. Currently, The following Anti-Aliased drawing primitives are available: AA-line AA-circle AA-ellipse AA-polygon (not filled) #### [[[ Interface ]]]
    Note: all ___Color routines expect the color to be in format 0xRRGGBBAA

     Pixel

       int pixelColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    			      Uint32 color);
       int pixelRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, Uint8 r,
    			     Uint8 g, Uint8 b, Uint8 a);

     Horizontal line

       int hlineColor(SDL_Surface * dst, Sint16 x1, Sint16 x2,
    			      Sint16 y, Uint32 color);
       int hlineRGBA(SDL_Surface * dst, Sint16 x1, Sint16 x2,
    			     Sint16 y, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Vertical line

       int vlineColor(SDL_Surface * dst, Sint16 x, Sint16 y1,
    			      Sint16 y2, Uint32 color);
       int vlineRGBA(SDL_Surface * dst, Sint16 x, Sint16 y1,
    			     Sint16 y2, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Rectangle

       int rectangleColor(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    				  Sint16 x2, Sint16 y2, Uint32 color);
       int rectangleRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    				 Sint16 x2, Sint16 y2, Uint8 r, Uint8 g,
    				 Uint8 b, Uint8 a);

     Filled rectangle (Box)

       int boxColor(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    			    Sint16 x2, Sint16 y2, Uint32 color);
       int boxRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2,
    			   Sint16 y2, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Line

       int lineColor(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    			     Sint16 x2, Sint16 y2, Uint32 color);
       int lineRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    			    Sint16 x2, Sint16 y2, Uint8 r, Uint8 g, Uint8 b,
    			    Uint8 a);

     AA Line
       int aalineColor(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    			       Sint16 x2, Sint16 y2, Uint32 color);
       int aalineRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1,
    			      Sint16 x2, Sint16 y2, Uint8 r, Uint8 g, Uint8 b,
    			      Uint8 a);

     Circle

       int circleColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    			       Sint16 r, Uint32 color);
       int circleRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    			      Sint16 rad, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     AA Circle

       int aacircleColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				 Sint16 r, Uint32 color);
       int aacircleRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    				Sint16 rad, Uint8 r, Uint8 g, Uint8 b,
    				Uint8 a);

     Filled Circle

       int filledCircleColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				     Sint16 r, Uint32 color);
       int filledCircleRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    				    Sint16 rad, Uint8 r, Uint8 g, Uint8 b,
    				    Uint8 a);

     Ellipse

       int ellipseColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				Sint16 rx, Sint16 ry, Uint32 color);
       int ellipseRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    			       Sint16 rx, Sint16 ry, Uint8 r, Uint8 g,
    			       Uint8 b, Uint8 a);

     AA Ellipse

       int aaellipseColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				  Sint16 rx, Sint16 ry, Uint32 color);
       int aaellipseRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    				 Sint16 rx, Sint16 ry, Uint8 r, Uint8 g,
    				 Uint8 b, Uint8 a);

     Filled Ellipse

       int filledEllipseColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				      Sint16 rx, Sint16 ry, Uint32 color);
       int filledEllipseRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    				     Sint16 rx, Sint16 ry, Uint8 r, Uint8 g,
    				     Uint8 b, Uint8 a);
     Pie

       int pieColor(SDL_Surface * dst, Sint16 x, Sint16 y, Sint16 rad,
    		   Sint16 start, Sint16 end, Uint32 color);
       int pieRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, Sint16 rad,
    		   Sint16 start, Sint16 end, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Filled Pie

       int filledPieColor(SDL_Surface * dst, Sint16 x, Sint16 y, Sint16 rad,
    		   Sint16 start, Sint16 end, Uint32 color);
       int filledPieRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, Sint16 rad,
    		   Sint16 start, Sint16 end, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Trigon

        int trigonColor(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3, Uint32 color);
        int trigonRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3,
    				 Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     AA-Trigon

        int aatrigonColor(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3, Uint32 color);
        int aatrigonRGBA(SDL_Surface * dst,  Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3,
    				   Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Filled Trigon

        int filledTrigonColor(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3, int color);
        int filledTrigonRGBA(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Sint16 x3, Sint16 y3,
    				       Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Polygon

       int polygonColor(SDL_Surface * dst, Sint16 * vx, Sint16 * vy,
    				int n, Uint32 color);
       int polygonRGBA(SDL_Surface * dst, Sint16 * vx, Sint16 * vy,
    			       int n, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     AA-Polygon

       int aapolygonColor(SDL_Surface * dst, Sint16 * vx, Sint16 * vy,
    				int n, Uint32 color);
       int aapolygonRGBA(SDL_Surface * dst, Sint16 * vx, Sint16 * vy,
    		 	       int n, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     Filled Polygon

       int filledPolygonColor(SDL_Surface * dst, Sint16 * vx,
    				      Sint16 * vy, int n, int color);
       int filledPolygonRGBA(SDL_Surface * dst, Sint16 * vx,
    				     Sint16 * vy, int n, Uint8 r, Uint8 g,
    				     Uint8 b, Uint8 a);

     Bezier Curve

        int bezierColor(SDL_Surface * dst, Sint16 * vx,
    				Sint16 * vy, int n, int s, Uint32 color);
        int bezierRGBA(SDL_Surface * dst, Sint16 * vx, Sint16 * vy,
                                     int n, int s, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

     8x8 Characters/Strings

       int characterColor(SDL_Surface * dst, Sint16 x, Sint16 y,
    				  char c, Uint32 color);
       int characterRGBA(SDL_Surface * dst, Sint16 x, Sint16 y,
    				 char c, Uint8 r, Uint8 g, Uint8 b, Uint8 a);
       int stringColor(SDL_Surface * dst, Sint16 x, Sint16 y, char *c,
    			       Uint32 color);
       int stringRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, char *c,
    			      Uint8 r, Uint8 g, Uint8 b, Uint8 a);

       void gfxPrimitivesSetFont(unsigned char *fontdata, int cw, int ch);
### Notes on Rotozoomer The rotozoom without interpolation code should be fast enough even for some realtime effects if the CPU is fast or bitmaps small. With interpolation the routines are typically used for pre-rendering stuff in higher quality (i.e. smoothing) - that's also a reason why the API differs from SDL_BlitRect() and creates a new target surface each time rotozoom is called. The final rendering speed is dependent on the target surface size as it is beeing xy-scanned when rendering the new surface. Note also that the smoothing toggle is dependent on the input surface bit depth. 8bit surfaces will never be smoothed - only 32bit surfaces will. Note that surfaces of other bit depth then 8 and 32 will be converted on the fly to a 32bit surface using a blit into a temporary surface. This impacts performance somewhat. #### [[[ Interface ]]]
    SDL_Surface * rotozoomSurface (SDL_Surface *src, double angle, double zoom, int smooth);

     Rotates and zoomes a 32bit or 8bit 'src' surface to newly created 'dst' surface.
     'angle' is the rotation in degrees. 'zoom' a scaling factor. If 'smooth' is 1
     then the destination 32bit surface is anti-aliased. If the surface is not 8bit
     or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly.

    SDL_Surface * rotozoomSurfaceXY (SDL_Surface *src, double angle, double zoomx, double zoomy, int smooth);

     Rotates and zoomes a 32bit or 8bit 'src' surface to newly created 'dst' surface.
     'angle' is the rotation in degrees. 'zoomx' and 'zoomy' are scaling factors that
     can also be negative. In this case the corresponding axis is flipped.  If 'smooth'
     is 1 then the destination 32bit surface is anti-aliased. If the surface is not 8bit
     or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly.

     Note: Flipping currently only works with antialiasing turned off.

    SDL_Surface * zoomSurface (SDL_Surface *src, double zoomx, double zoomy, int smooth);

     Zoomes a 32bit or 8bit 'src' surface to newly created 'dst' surface.
     'zoomx' and 'zoomy' are scaling factors for width and height. If 'smooth' is 1
     then the destination 32bit surface is anti-aliased. If the surface is not 8bit
     or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly.

    Smoothing (interpolation) flags work only on 32bit surfaces:

     #define SMOOTHING_OFF		0
     #define SMOOTHING_ON		1
### Notes on framerate functions The framerate functions are used to insert delays into the graphics loop to maintain a constant framerate. The implementation is more sophisticated that the usual
    	SDL_Delay(1000/FPS);
call since these functions keep track of the desired game time per frame for a linearly interpolated sequence of future timing points of each frame. This is done to avoid rounding errors from the inherent instability in the delay generation and application - i.e. the 100th frame of a game running at 50Hz will be accurately 2.00sec after the 1st frame (if the machine can keep up with the drawing). See also the diagram for more details on this.
Framerate Calc. Diagram
#### [[[ Interface ]]]
    The functions return 0 or value for sucess and -1 for error. All functions
    use a pointer to a framerate-manager variable to operate.

    void SDL_initFramerate(FPSmanager * manager);

     Initialize the framerate manager, set default framerate of 30Hz and
     reset delay interpolation.

    int SDL_setFramerate(FPSmanager * manager, int rate);

     Set a new framerate for the manager and reset delay interpolation.

    int SDL_getFramerate(FPSmanager * manager);

     Get the currently set framerate of the manager.

    void SDL_framerateDelay(FPSmanager * manager);

     Generate a delay to accomodate currently set framerate. Call once in the
     graphics/rendering loop. If the computer cannot keep up with the rate (i.e.
     drawing too slow), the delay is zero and the delay interpolation is reset.
### Notes on imageFilter functions The imagefilter functions are a collection of MMX optimized routines that operate on continuous buffers of bytes - typically greyscale images from framegrabbers and such - performing functions such as image addition and binarization. All functions (almost .. not the the convolution routines) have a C implementation that is automatically used on systems without MMX capabilities. #### [[[ Interface ]]]
    Comments:
      1.) MMX functions work best if all data blocks are aligned on a 32 bytes boundary.
      2.) Data that is not within an 8 byte boundary is processed using the C routine.
      3.) Convolution routines do not have C routines at this time.
      4.) All routines return 0 for OK and -1 for error.

    Detect MMX capability in CPU

      int SDL_imageFilterMMXdetect(void);

    Force use of MMX off (or turn possible use back on)

      void SDL_imageFilterMMXoff(void);
      void SDL_imageFilterMMXon(void);

    SDL_imageFilterAdd: D = saturation255(S1 + S2)

      int SDL_imageFilterAdd (unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterMean: D = S1/2 + S2/2

      int SDL_imageFilterMean(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterSub: D = saturation0(S1 - S2)

      int SDL_imageFilterSub(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterAbsDiff: D = | S1 - S2 |

      int SDL_imageFilterAbsDiff(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterMult: D = saturation(S1 * S2)

      int SDL_imageFilterMult(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterMultNor: D = S1 * S2   (non-MMX)

      int SDL_imageFilterMultNor(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterMultDivby2: D = saturation255(S1/2 * S2)

      int SDL_imageFilterMultDivby2(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterMultDivby4: D = saturation255(S1/2 * S2/2)

      int SDL_imageFilterMultDivby4(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterBitAnd: D = S1 & S2

      int SDL_imageFilterBitAnd(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterBitOr: D = S1 | S2

      int SDL_imageFilterBitOr(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterDiv: D = S1 / S2   (non-MMX)

      int SDL_imageFilterDiv(unsigned char *Src1, unsigned char *Src2, unsigned char *Dest, int length);

    SDL_imageFilterBitNegation: D = !S

      int SDL_imageFilterBitNegation(unsigned char *Src1, unsigned char *Dest, int length);

    SDL_imageFilterAddByte: D = saturation255(S + C)

      int SDL_imageFilterAddByte(unsigned char *Src1, unsigned char *Dest, int length, unsigned char C);

    SDL_imageFilterAddByteToHalf: D = saturation255(S/2 + C)

      int SDL_imageFilterAddByteToHalf(unsigned char *Src1, unsigned char *Dest, int length, unsigned char C);

    SDL_imageFilterSubByte: D = saturation0(S - C)

      int SDL_imageFilterSubByte(unsigned char *Src1, unsigned char *Dest, int length, unsigned char C);

    SDL_imageFilterShiftRight: D = saturation0(S >> N)

      int SDL_imageFilterShiftRight(unsigned char *Src1, unsigned char *Dest, int length, unsigned char N);

    SDL_imageFilterMultByByte: D = saturation255(S * C)

      int SDL_imageFilterMultByByte(unsigned char *Src1, unsigned char *Dest, int length, unsigned char C);

    SDL_imageFilterShiftRightAndMultByByte: D = saturation255((S >> N) * C)

      int SDL_imageFilterShiftRightAndMultByByte(unsigned char *Src1, unsigned char *Dest, int length, unsigned char N, unsigned char C);

    SDL_imageFilterShiftLeftByte: D = (S << N)

      int SDL_imageFilterShiftLeftByte(unsigned char *Src1, unsigned char *Dest, int length, unsigned char N);

    SDL_imageFilterShiftLeft: D = saturation255(S << N)

      int SDL_imageFilterShiftLeft(unsigned char *Src1, unsigned char *Dest, int length, unsigned char N);

    SDL_imageFilterBinarizeUsingThreshold: D = S >= T ? 255:0

      int SDL_imageFilterBinarizeUsingThreshold(unsigned char *Src1, unsigned char *Dest, int length, unsigned char T);

    SDL_imageFilterClipToRange: D = (S >= Tmin) & (S <= Tmax) 255:0

      int SDL_imageFilterClipToRange(unsigned char *Src1, unsigned char *Dest, int length, unsigned char Tmin, unsigned char Tmax);

    SDL_imageFilterNormalizeLinear: D = saturation255((Nmax - Nmin)/(Cmax - Cmin)*(S - Cmin) + Nmin)

      int SDL_imageFilterNormalizeLinear(unsigned char *Src1, unsigned char *Dest, int length, int Cmin, int Cmax, int Nmin, int Nmax);

     !!! NO C-ROUTINE FOR THESE FUNCTIONS YET !!!

    SDL_imageFilterConvolveKernel3x3Divide: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel3x3Divide(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                          signed short *Kernel, unsigned char Divisor);

    SDL_imageFilterConvolveKernel5x5Divide: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel5x5Divide(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                          signed short *Kernel, unsigned char Divisor);

    SDL_imageFilterConvolveKernel7x7Divide: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel7x7Divide(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                signed short *Kernel, unsigned char Divisor);

    SDL_imageFilterConvolveKernel9x9Divide: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel9x9Divide(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                signed short *Kernel, unsigned char Divisor);

    SDL_imageFilterConvolveKernel3x3ShiftRight: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel3x3ShiftRight(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                    signed short *Kernel, unsigned char NRightShift);

    SDL_imageFilterConvolveKernel5x5ShiftRight: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel5x5ShiftRight(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                    signed short *Kernel, unsigned char NRightShift);

    SDL_imageFilterConvolveKernel7x7ShiftRight: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel7x7ShiftRight(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                    signed short *Kernel, unsigned char NRightShift);

    SDL_imageFilterConvolveKernel9x9ShiftRight: Dij = saturation0and255( ... )

      int SDL_imageFilterConvolveKernel9x9ShiftRight(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                                    signed short *Kernel, unsigned char NRightShift);

    SDL_imageFilterSobelX: Dij = saturation255( ... )

      int SDL_imageFilterSobelX(unsigned char *Src, unsigned char *Dest, int rows, int columns);

    SDL_imageFilterSobelXShiftRight: Dij = saturation255( ... )

      int SDL_imageFilterSobelXShiftRight(unsigned char *Src, unsigned char *Dest, int rows, int columns,
                         unsigned char NRightShift);

    Align/restore stack to 32 byte boundary -- Functionality untested! --

      void SDL_imageFilterAlignStack(void);
      void SDL_imageFilterRestoreStack(void);
### Installation and Test To compile the library your need the SDL 1.2 installed from source or with the 'devel' RPM package. Run
    	./autogen.sh
    	./configure
    	make
to compile the library. Run the shell script 'nodebug.sh' before make, to patch the makefile for optimized compilation. Run
    	make install
    	ldconfig
to install the library. The default location for the installation is /usr/local/lib and /usr/local/include (for Linux). To create a Windows DLL using VisualC:
            vcvars.bat
    	copy VisualC/makefile
       	nmake
To create a Windows DLL using the xmingw32 cross-compiler:
            cross-configure
            cross-make
            cross-make install
Change to the ./Test directory and run
    	./configure
    	make
to create several test programs for the libraries functions. To build without MMX code enabled (i.e. PPC architecture):
            ./configure --disable-mmx
            make
            make install
To build on MacOS X with Project Builder, follow these steps: Update your developer tools to the lastest version (December 2002 as of this revision). Install the SDL Developers framework for Mac OS X. Download the latest SDL_gfx source distribution and extract the archive in a convenient location. Extract the included OSX-PB.tgz archive into the top directory of the SDL_gfx distribution (from step 3). This will create a PB that contains the project files. The project has targets for the SDL_gfx framework and the four test programs. All can be built using the 'deployment' or 'development' build styles. ### Change Log
    CHANGES/VERSION
    ===============

    Ver 2.0.13 - Tue Dec 21 08:41:25 EST 2004
    * changed include back to "SDL.h"
    * compile fixes for OSX fink  (thanks (Michael)
    * compile fixes for gcc3.4 (thanks Dries)
    * support vertical and horizontal flipping of axis in new
      rotozoomSurfaceXY function (thanks Victor)
    * updated TestRotozoom program

    Ver 2.0.12 - Mon Aug 30 09:04:11 EDT 2004
    * piecolor naming fix
    * primitive API change to 'filledPie'
    * introduction of some const variables

    Ver 2.0.11 - Thu May 13 09:42:34 EDT 2004
    * added pieRGBA/pieColor primitive (non filled pie)
    * added QNX6 build patch
    * use $(includedir)/SDL to automake setup
    * updated README
    * added 2x2 box & pie tests
    * added dynamic font setup routine
    * added sample font files to the Fonts directory
    * added font test program
    * string routines changed to use const char
    * fixed TestRotozoom clear color bug

    Ver 2.0.10 - Thu Dec 11 09:40:08 EST 2003
    * updated "missing" script to newer version to avoid build errors
    * fixed filled polygon int32 overflow error in calculation
    * updated RPM spec file for new website path
    * added micro version number to .h file

    Ver 2.0.9 - Mon Oct 27 10:03:18 EST 2003
    * Fixed "filled-box width too small by 1 bug" for A=255
    * Wrong versioning in .h file

    Ver 2.0.8 - Wed Jul 16 16:18:13 EDT 2003
    * Modified filledPolygon drawing
      (The edges of a filled polygon and a polyline were
       reported to not intersect correctly. With this fix, the
       edges do still do not intersect 100% due to the difference
       in the algorithms. But now a polygon will never draw
       outside of the area enclosed by a polyline.)

    Ver 2.0.7 - Sun Jun  8 08:17:38 EDT 2003
    * Added MacOS X Project Builder code
    * changed SDL include to
    * added bezier curve

    Ver 2.0.6 - Sat May 25 15:12:17 EDT 2002
    * Fixed clipping code for most primitives
    * Added clipping code for character
    * Added VC7 project file

    Ver 2.0.5 - n/a
    * Removed some unused code

    Ver 2.0.4 - Sat Feb  9 22:09:45 EST 2002
    * Fixed rectangle drawing bug on edges for A<255
    * Added trigons (triangles) as wrapper calls to polygon.

    Ver 2.0.3 - Sat Jan 26 10:06:16 EST 2002
    * Zipped VisualC directory to avoid EOL problems.
    * Fixed aalineColor call (y2 parameter was y1).
    * Fixed rotozoom bug that caused black or undefined pixels on edges.

    Ver 2.0.2 - Sat Jan 19 21:41:28 EST 2002
    * Removed dependency from GL libraries during compile.
    * Added VisualC makefile.

    Ver 2.0 - Sat Dec 29 16:27:57 EST 2001

    * Initial release of SDL_gfx based on SDL_gfxPrimitives and SDL_rotozoom
      code.
    * Added framerate code and testprogram.
    * Added imageFilters code and testprogram.
    * New distribution: source code, README, configure system etc.

    Previous versions
    =================

    SDL_gfxPrimitives:
    ------------------

    Ver 1.5 - Mon Jul  2 11:27:40 EDT 2001

    * New alpha blending code for factor 4 speedups if a<255 on all functions.
    * Modified include file for W32 DLL support.
    * Added VC6 project files for DLL and static library building.
    * Added simple AA-circle/-ellipse routine - quality needs improvement.
    * Removed 32bit shift on 64bit number from aaline for better portability
      across platforms.
    * Removed a couple more compiler warnings (i.e. purely cosmetic fix).

    Ver 1.4 - Sun Jun  3 11:52:07 EDT 2001

    * Fixed hline, vline and rectangle clipping and result codes.
    * Fixed AA-line arithmetic (was alpha subtraction, should be alpha ratio).
    * More caching on fonts for speedups.
    * More pointer checks in several places.
    * New special cases for ellipses for rx=0/ry=0.
    * Same sanity checks for circles/ellipses.
    * Same return code for polygon/filledpolygon.

    Ver 1.3 - Thu May 31 12:41:35 EDT 2001

    * Minor cleanups and fixes (gcc -Wall is your friend).

    Ver 1.2 again - Thu Apr  5 07:50:57 EDT 2001

    * Fixed lineRGBA and aalineRGBA calls (had coordinate-passing mixed up twice,
      thanks Lion for pointing this out)

    Ver 1.2 - Wed Apr  4 08:32:42 EDT 2001

    * Changed to a dual, you-have-the-choice(TM) licencing system
      to accomodate GPL developments using SDL_gfxPrimitives.
    * Some minor fixes (thanks Karl).
    * All routines return proper result code now.
    * Clipping for aaline, circle and ellipse.

    Ver 1.1 - Thu Mar 22 15:28:27 EST 2001

    * Added code for Alpha=255 pixel drawing through direct memory writes to all routines
    resulting in a much faster performance (factor 5 to 20) for non transparent pixels.
    * New test and benchmark program with better info and nicer look.
    * More info in README. Proper licence file. Comment cleanup.

    Ver 1.0 - Fri Mar 16 08:38:07 EST 2001

    * Initial release

    SDL_rotozoom:
    -------------

    Ver 1.6 - Mon Nov 19 21:19:26 EST 2001
    * Added interpolation to alpha channel (simplifies code)
    * Ran the sourcecode through 'indent' for better readability

    Ver 1.5 - Sat Jul  7 13:02:07 EDT 2001
    * Added project files (VisualC.zip) and modifications for VC project building.
    * Fixed old versioning in configure.in file.
    * Fixed LICENSE file and LGPL source reference.

    Ver 1.4 - Mon Jun  4 12:15:31 EDT 2001
    * Removed SDL_SoftStretch call again in favour of an internal zoom routine.
    * Added new zoomSurface() function with seperate X and Y zoom factors.

    Ver 1.3 - Thu May 31 08:37:36 EDT 2001
    * Modified code to handle RGBA or ABGR source surfaces transparently.
    * More error checking, source surface locking.
    * Slighly expanded test program with event handling.

    Ver 1.2 - Wed May 30 18:18:05 EDT 2001
    * Fixed the completely broken 32bit routine's pointer arithmetic.
    * Uses SDL_SoftStretch in certain cases (angle=0, smooth=0).
    * Convert source surface on the fly if not 8/32bit.
    * Added license file - was empty before (duh).

    Ver 1.1 - Wed May 23 15:04:42 EDT 2001
    * Added automake/autoconf scripts and testprogram.

    Ver 1.0 - Fri Mar 16 08:16:06 EST 2001
    * Initial release
### Thanks This library is used in the AppWares Development Group's IMP product and thanks goes out out to them for supporting this project - please visit http://www.appwares.com for more information. ### Contributors * Fix for filledbox by Ingo van Lil, inguin at gmx.de - thanks Ingo. * Non-alpha line drawing code adapted from routine by Pete Shinners, pete at shinners.org - thanks Pete. * More fixes by Karl Bartel, karlb at gmx.net - thanks Karl. * Much testing and suggestions for fixes from Danny van Bruggen, danny at froukepc.dhs.org - thanks Danny. * AA-circle/-ellipse code idea from Stephane Magnenat, nct at wg0.ysagoon.com - thanks Stephane. * Faster blending routines contributed by Anders Lindström, cal at swipnet.se - thanks Anders. * VisualC makefile contributed by Danny van Bruggen, danny at froukepc.dhs.org - thanks Danny. * VisualC7 project file contributed by James Turk, jturk at conceptofzero.com - thanks James. * Project Builder package contributed by Thomas Tongue, TTongue at imagiware.com - Thanks Thomas. * Fix for filledPolygon contributed by Kentaro Fukuchi fukuchi at is.titech.ac.jp - Thanks Kentaro. * QNX6 patch contributed by Mike Gorchak, mike at malva.ua - Thanks Mike. * Pie idea contributed by Eike Lange, eike.lange at uni-essen.de - Thanks Eike. * Dynamic font setup by Todor Prokopov, koprok at dir.bg - Thanks Todor. * Horizontal/Vertical flipping code by Victor (Haypo) Stinner, victor.stinner at haypocalc.com - Thanks Victor. * OSX build fixes by Michael Wybrow, mjwybrow at cs.mu.oz.au - Thanks Michael. * gcc3.4 build fixes by Dries Verachtert, dries at ulyssis.org - Thanks Dries.