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pamdraw.h
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/* pamdraw.h - header file for simple drawing routines in libnetpbm. ** ** Simple, yes, and also fairly slow if the truth be told; but also very ** flexible and powerful. ** ** The two basic concepts are the drawproc and clientdata. All the drawing ** routines take a drawproc that does the actual drawing. A drawproc draws ** a single point, and it looks like this: */ #include <netpbm/pm_config.h> #ifdef __cplusplus extern "C" { #endif #if 0 } /* to fake out automatic code indenters */ #endif typedef struct { int x; int y; } pamd_point; static __inline__ pamd_point pamd_makePoint(int const x, int const y) { pamd_point p; p.x = x; p.y = y; return p; } void pamd_validateCoord(int const c); void pamd_validatePoint(pamd_point const p); typedef enum { PAMD_PATHLEG_LINE } pamd_pathlegtype; struct pamd_linelegparms { pamd_point end; }; typedef struct { /*---------------------------------------------------------------------------- A leg of a pamd_path. -----------------------------------------------------------------------------*/ pamd_pathlegtype type; union { struct pamd_linelegparms linelegparms; } u; } pamd_pathleg; typedef struct { /*---------------------------------------------------------------------------- A closed path -----------------------------------------------------------------------------*/ unsigned int version; /* Must be zero. For future expansion. */ pamd_point begPoint; unsigned int legCount; /* Number of legs in the path; i.e. size of 'legs' array */ size_t legSize; /* Size of storage occupied by one pamd_pathleg. I.e. sizeof(pamd_pathleg). Used for binary backward compatibility between callers and libpamd as the definition of pamd_pathleg changes. */ pamd_pathleg * legs; } pamd_path; typedef void pamd_drawproc(tuple **, unsigned int, unsigned int, unsigned int, sample, pamd_point, const void *); pamd_drawproc pamd_point_drawproc; /* ** So, you call a drawing routine, e.g. pamd_line(), and pass it a drawproc; ** it calls the drawproc for each point it wants to draw. Why so complicated? ** Because you can define your own drawprocs to do more interesting things than ** simply draw the point. For example, you could make one that calls back into ** another drawing routine, say pamd_circle() to draw a circle at each point ** of a line. ** ** Slow? Well sure, we're talking results here, not realtime. You can do ** tricks with this arrangement that you couldn't even think of before. ** Still, to speed things up for the 90% case you can use this: */ #define PAMD_NULLDRAWPROC NULL /* ** Just like pamd_point_drawproc() it simply draws the point, but it's done ** inline, and clipping is assumed to be handled at a higher level. ** ** Now, what about clientdata. Well, it's an arbitrary pointer, and can ** mean something different to each different drawproc. For the above two ** drawprocs, clientdata should be a pointer to a tuple holding the color ** to be drawn. Other drawprocs can use it to point to something else, ** e.g. some structure to be modified, or they can ignore it. */ /* Outline drawing routines. Lines, splines, circles, etc. */ int pamd_setlinetype(int const type); #define PAMD_LINETYPE_NORMAL 0 #define PAMD_LINETYPE_NODIAGS 1 /* If you set NODIAGS, all tuples drawn by pamd_line() will be 4-connected ** instead of 8-connected; in other words, no diagonals. This is useful ** for some applications, for example when you draw many parallel lines ** and you want them to fit together without gaps. */ int pamd_setlineclip(int const clip); #define pamd_setlineclipping(x) pamd_setlineclip(x) /* Normally, pamd_line() clips to the edges of the pixmap. You can use this ** routine to disable the clipping, for example if you are using a drawproc ** that wants to do its own clipping. */ void pamd_line(tuple ** const tuples, int const cols, int const rows, int const depth, sample const maxval, pamd_point const p0, pamd_point const p1, pamd_drawproc drawProc, const void * const clientdata); /* Draws a line from p0 to p1. */ void pamd_spline3(tuple ** const tuples, int const cols, int const rows, int const depth, sample const maxval, pamd_point const p0, pamd_point const p1, pamd_point const p2, pamd_drawproc drawProc, const void * const clientdata); /* Draws a three-point spline from p0 to p2, with p1 as the control point. All drawing is done via pamd_line(), so the routines that control it control pamd_spline3p() as well. */ void pamd_polyspline(tuple ** const tuples, unsigned int const cols, unsigned int const rows, unsigned int const depth, sample const maxval, pamd_point const p0, unsigned int const nc, pamd_point * const c, pamd_point const p1, pamd_drawproc drawProc, const void * const clientdata); /* Draws a bunch of splines end to end. p0 and p1 are the initial and final points, and the c[] are the intermediate control points. nc is the number of these control points. */ void pamd_spline4(tuple ** const tuples, unsigned int const cols, unsigned int const rows, unsigned int const depth, sample const maxval, pamd_point const endPt0, pamd_point const endPt1, pamd_point const ctlPt0, pamd_point const ctlPt1, pamd_drawproc drawProc, const void * const clientdata); void pamd_circle(tuple ** const tuples, unsigned int const cols, unsigned int const rows, unsigned int const depth, sample const maxval, pamd_point const center, unsigned int const radius, pamd_drawproc drawProc, const void * const clientData); /* Draws a circle centered at 'center' with radius 'radius' */ /* Simple filling routines. */ void pamd_filledrectangle(tuple ** const tuples, int const cols, int const rows, int const depth, sample const maxval, int const left, int const top, int const width, int const height, pamd_drawproc drawProc, const void * const clientdata); /* Fills in the rectangle [left, top, width, height]. */ void pamd_fill_path(tuple ** const tuples, int const cols, int const rows, int const depth, sample const maxval, pamd_path * const pathP, tuple const color); /* Fills in a closed path. Not much different from pamd_fill(), but with a different interface. */ /* Arbitrary filling routines. With these you can fill any outline that ** you can draw with the outline routines. */ struct fillobj; struct fillobj * pamd_fill_create(void); /* Returns a blank fillhandle. */ void pamd_fill_destroy(struct fillobj * fillObjP); void pamd_fill_drawproc(tuple ** const tuples, unsigned int const cols, unsigned int const rows, unsigned int const depth, sample const maxval, pamd_point const p, const void * const clientdata); /* Use this drawproc to trace the outline you want filled. Use the fillhandle as the clientdata. */ void pamd_fill(tuple ** const tuples, int const cols, int const rows, int const depth, sample const maxval, struct fillobj * const fillObjP, pamd_drawproc drawProc, const void * const clientdata); /* Once you've traced the outline, give the fillhandle to this routine to do the actual drawing. As usual, it takes a drawproc and clientdata; you could define drawprocs to do stipple fills and such. */ /* Text drawing routines. */ void pamd_text(tuple** const tuples, int const cols, int const rows, int const depth, sample const maxval, pamd_point const pos, int const height, int const angle, const char * const sArg, pamd_drawproc drawProc, const void * const clientdata); /* Draws the null-terminated string 's' left justified at the point ('x', 'y'). The text will be 'height' tuples high and will be aligned on a baseline inclined 'angle' degrees with the X axis. The supplied drawproc and clientdata are passed to pamd_line() which performs the actual drawing. */ void pamd_text_box(int const height, int const angle, const char * const s, int * const leftP, int * const topP, int * const rightP, int * const bottomP); /* Calculates the extents box for text drawn by pamd_text with the given string, size, and orientation. Most extent box calculations should use an angle specification of zero to calculate the unrotated box enclosing the text. If you need the extents of rotated text, however, you can call pamd_text_box with a nonzero angle. */ #ifdef __cplusplus } #endif