dlls/gdiplus/gdiplus.c

   1 /*
   2  * Copyright (C) 2007 Google (Evan Stade)
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  17  */
  18
  19 #include <stdarg.h>
  20 #include <math.h>
  21
  22 #include "windef.h"
  23 #include "winbase.h"
  24 #include "winerror.h"
  25 #include "wine/debug.h"
  26 #include "wingdi.h"
  27
  28 #include "objbase.h"
  29
  30 #include "gdiplus.h"
  31 #include "gdiplus_private.h"
  32
  33 WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);
  34
  35 /*****************************************************
  36  *      DllMain
  37  */
  38 BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
  39 {
  40     TRACE("(%p, %d, %p)\n", hinst, reason, reserved);
  41
  42     switch(reason)
  43     {
  44     case DLL_WINE_PREATTACH:
  45         return FALSE;  /* prefer native version */
  46
  47     case DLL_PROCESS_ATTACH:
  48         DisableThreadLibraryCalls( hinst );
  49         break;
  50     }
  51     return TRUE;
  52 }
  53
  54 /*****************************************************
  55  *      GdiplusStartup [GDIPLUS.@]
  56  */
  57 Status WINAPI GdiplusStartup(ULONG_PTR *token, const struct GdiplusStartupInput *input,
  58                              struct GdiplusStartupOutput *output)
  59 {
  60     if(!token)
  61         return InvalidParameter;
  62
  63     if(input->GdiplusVersion != 1) {
  64         return UnsupportedGdiplusVersion;
  65     } else if ((input->DebugEventCallback) ||
  66         (input->SuppressBackgroundThread) || (input->SuppressExternalCodecs)){
  67         FIXME("Unimplemented for non-default GdiplusStartupInput\n");
  68         return NotImplemented;
  69     } else if(output) {
  70         FIXME("Unimplemented for non-null GdiplusStartupOutput\n");
  71         return NotImplemented;
  72     }
  73
  74     return Ok;
  75 }
  76
  77 /*****************************************************
  78  *      GdiplusShutdown [GDIPLUS.@]
  79  */
  80 void WINAPI GdiplusShutdown(ULONG_PTR token)
  81 {
  82     /* FIXME: no object tracking */
  83 }
  84
  85 /*****************************************************
  86  *      GdipAlloc [GDIPLUS.@]
  87  */
  88 void* WINGDIPAPI GdipAlloc(SIZE_T size)
  89 {
  90     return HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, size);
  91 }
  92
  93 /*****************************************************
  94  *      GdipFree [GDIPLUS.@]
  95  */
  96 void WINGDIPAPI GdipFree(void* ptr)
  97 {
  98     HeapFree(GetProcessHeap(), 0, ptr);
  99 }
 100
 101 /* Calculates the bezier points needed to fill in the arc portion starting at
 102  * angle start and ending at end.  These two angles should be no more than 90
 103  * degrees from each other.  x1, y1, x2, y2 describes the bounding box (upper
 104  * left and width and height).  Angles must be in radians. write_first indicates
 105  * that the first bezier point should be written out (usually this is false).
 106  * pt is the array of GpPointFs that gets written to.
 107  **/
 108 static void add_arc_part(GpPointF * pt, REAL x1, REAL y1, REAL x2, REAL y2,
 109     REAL start, REAL end, BOOL write_first)
 110 {
 111     REAL center_x, center_y, rad_x, rad_y, cos_start, cos_end,
 112         sin_start, sin_end, a, half;
 113     INT i;
 114
 115     rad_x = x2 / 2.0;
 116     rad_y = y2 / 2.0;
 117     center_x = x1 + rad_x;
 118     center_y = y1 + rad_y;
 119
 120     cos_start = cos(start);
 121     cos_end = cos(end);
 122     sin_start = sin(start);
 123     sin_end = sin(end);
 124
 125     half = (end - start) / 2.0;
 126     a = 4.0 / 3.0 * (1 - cos(half)) / sin(half);
 127
 128     if(write_first){
 129         pt[0].X = cos_start;
 130         pt[0].Y = sin_start;
 131     }
 132     pt[1].X = cos_start - a * sin_start;
 133     pt[1].Y = sin_start + a * cos_start;
 134
 135     pt[3].X = cos_end;
 136     pt[3].Y = sin_end;
 137     pt[2].X = cos_end + a * sin_end;
 138     pt[2].Y = sin_end - a * cos_end;
 139
 140     /* expand the points back from the unit circle to the ellipse */
 141     for(i = (write_first ? 0 : 1); i < 4; i ++){
 142         pt[i].X = pt[i].X * rad_x + center_x;
 143         pt[i].Y = pt[i].Y * rad_y + center_y;
 144     }
 145 }
 146
 147 /* We plot the curve as if it is on a circle then stretch the points.  This
 148  * adjusts the angles so that when we stretch the points they will end in the
 149  * right place. This is only complicated because atan and atan2 do not behave
 150  * conveniently. */
 151 static void unstretch_angle(REAL * angle, REAL rad_x, REAL rad_y)
 152 {
 153     REAL stretched;
 154     INT revs_off;
 155
 156     *angle = deg2rad(*angle);
 157
 158     if(fabs(cos(*angle)) < 0.00001 || fabs(sin(*angle)) < 0.00001)
 159         return;
 160
 161     stretched = gdiplus_atan2(sin(*angle) / fabs(rad_y), cos(*angle) / fabs(rad_x));
 162     revs_off = roundr(*angle / (2.0 * M_PI)) - roundr(stretched / (2.0 * M_PI));
 163     stretched += ((REAL)revs_off) * M_PI * 2.0;
 164     *angle = stretched;
 165 }
 166
 167 /* Stores the bezier points that correspond to the arc in points.  If points is
 168  * null, just return the number of points needed to represent the arc. */
 169 INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
 170     REAL startAngle, REAL sweepAngle)
 171 {
 172     INT i, count;
 173     REAL end_angle, start_angle, endAngle;
 174
 175     endAngle = startAngle + sweepAngle;
 176     unstretch_angle(&startAngle, x2 / 2.0, y2 / 2.0);
 177     unstretch_angle(&endAngle, x2 / 2.0, y2 / 2.0);
 178
 179     count = ceilf(fabs(endAngle - startAngle) / M_PI_2) * 3 + 1;
 180     /* don't make more than a full circle */
 181     count = min(MAX_ARC_PTS, count);
 182
 183     if(count == 1)
 184         return 0;
 185     if(!points)
 186         return count;
 187
 188     /* start_angle and end_angle are the iterative variables */
 189     start_angle = startAngle;
 190
 191     for(i = 0; i < count - 1; i += 3){
 192         /* check if we've overshot the end angle */
 193         if( sweepAngle > 0.0 )
 194             end_angle = min(start_angle + M_PI_2, endAngle);
 195         else
 196             end_angle = max(start_angle - M_PI_2, endAngle);
 197
 198         add_arc_part(&points[i], x1, y1, x2, y2, start_angle, end_angle, i == 0);
 199
 200         start_angle += M_PI_2 * (sweepAngle < 0.0 ? -1.0 : 1.0);
 201     }
 202
 203     return count;
 204 }
 205
 206 COLORREF ARGB2COLORREF(ARGB color)
 207 {
 208     /*
 209     Packing of these color structures:
 210     COLORREF:   00bbggrr
 211     ARGB:       aarrggbb
 212     FIXME:doesn't handle alpha channel
 213     */
 214     return (COLORREF)
 215         ((color & 0x0000ff) << 16) +
 216          (color & 0x00ff00) +
 217         ((color & 0xff0000) >> 16);
 218 }
 219
 220 /* Like atan2, but puts angle in correct quadrant if dx is 0. */
 221 REAL gdiplus_atan2(REAL dy, REAL dx)
 222 {
 223     if((dx == 0.0) && (dy != 0.0))
 224         return dy > 0.0 ? M_PI_2 : -M_PI_2;
 225
 226     return atan2(dy, dx);
 227 }