| /* | |
| * LineDDA | |
| * | |
| * Copyright 1993 Bob Amstadt | |
| */ | |
| #include <stdlib.h> | |
| #include "windef.h" | |
| #include "wingdi.h" | |
| #include "wine/wingdi16.h" | |
| /********************************************************************** | |
| * LineDDA (GDI32.@) | |
| */ | |
| BOOL WINAPI LineDDA(INT nXStart, INT nYStart, INT nXEnd, INT nYEnd, | |
| LINEDDAPROC callback, LPARAM lParam ) | |
| { | |
| INT xadd = 1, yadd = 1; | |
| INT err,erradd; | |
| INT cnt; | |
| INT dx = nXEnd - nXStart; | |
| INT dy = nYEnd - nYStart; | |
| if (dx < 0) { | |
| dx = -dx; xadd = -1; | |
| } | |
| if (dy < 0) { | |
| dy = -dy; yadd = -1; | |
| } | |
| if (dx > dy) { /* line is "more horizontal" */ | |
| err = 2*dy - dx; erradd = 2*dy - 2*dx; | |
| for(cnt = 0;cnt <= dx; cnt++) { | |
| callback(nXStart,nYStart,lParam); | |
| if (err > 0) { | |
| nYStart += yadd; | |
| err += erradd; | |
| } else { | |
| err += 2*dy; | |
| } | |
| nXStart += xadd; | |
| } | |
| } else { /* line is "more vertical" */ | |
| err = 2*dx - dy; erradd = 2*dx - 2*dy; | |
| for(cnt = 0;cnt <= dy; cnt++) { | |
| callback(nXStart,nYStart,lParam); | |
| if (err > 0) { | |
| nXStart += xadd; | |
| err += erradd; | |
| } else { | |
| err += 2*dx; | |
| } | |
| nYStart += yadd; | |
| } | |
| } | |
| return TRUE; | |
| } |