[3/10] gdiplus: add GdipAddPathArc
Evan Stade
estade at gmail.com
Tue Jul 10 20:39:40 CDT 2007
Hi,
>From this point forward, this series depends on Paul Vriens's patch to
graphicspath.c.
Changelog:
*added GdipAddPathArc (implementation mostly in gdiplus.c as
GdipDrawArc also needs to use it)
dlls/gdiplus/gdiplus.c | 106 ++++++++++++++++++++++++++++++++++++++++
dlls/gdiplus/gdiplus.spec | 2 -
dlls/gdiplus/gdiplus_private.h | 3 +
dlls/gdiplus/graphicspath.c | 31 ++++++++++++
include/gdiplusflat.h | 1
5 files changed, 142 insertions(+), 1 deletions(-)
--
Evan Stade
-------------- next part --------------
diff --git a/dlls/gdiplus/gdiplus.c b/dlls/gdiplus/gdiplus.c
index 97136a1..19b72e0 100644
--- a/dlls/gdiplus/gdiplus.c
+++ b/dlls/gdiplus/gdiplus.c
@@ -23,6 +23,7 @@ #include "windef.h"
#include "winbase.h"
#include "winerror.h"
#include "wine/debug.h"
+#include "gdiplus_private.h"
#include "gdiplus.h"
WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);
@@ -116,3 +117,108 @@ inline REAL deg2rad(REAL degrees)
{
return M_PI * degrees / 180.0;
}
+
+/* Calculates the bezier points needed to fill in the arc portion starting at
+ * angle start and ending at end. These two angles should be no more than 90
+ * degrees from each other. x1, y1, x2, y2 describes the bounding box (upper
+ * left and width and height). Angles must be in radians. write_first indicates
+ * that the first bezier point should be written out (usually this is false).
+ * pt is the array of GpPointFs that gets written to.
+ **/
+static void add_arc_part(GpPointF * pt, REAL x1, REAL y1, REAL x2, REAL y2,
+ REAL start, REAL end, BOOL write_first)
+{
+ REAL center_x, center_y, rad_x, rad_y, cos_start, cos_end,
+ sin_start, sin_end, a, half;
+ INT i;
+
+ rad_x = x2 / 2.0;
+ rad_y = y2 / 2.0;
+ center_x = x1 + rad_x;
+ center_y = y1 + rad_y;
+
+ cos_start = cos(start);
+ cos_end = cos(end);
+ sin_start = sin(start);
+ sin_end = sin(end);
+
+ half = (end - start) / 2.0;
+ a = 4.0 / 3.0 * (1 - cos(half)) / sin(half);
+
+ if(write_first){
+ pt[0].X = cos_start;
+ pt[0].Y = sin_start;
+ }
+ pt[1].X = cos_start - a * sin_start;
+ pt[1].Y = sin_start + a * cos_start;
+
+ pt[3].X = cos_end;
+ pt[3].Y = sin_end;
+ pt[2].X = cos_end + a * sin_end;
+ pt[2].Y = sin_end - a * cos_end;
+
+ /* expand the points back from the unit circle to the ellipse */
+ for(i = (write_first ? 0 : 1); i < 4; i ++){
+ pt[i].X = pt[i].X * rad_x + center_x;
+ pt[i].Y = pt[i].Y * rad_y + center_y;
+ }
+}
+
+/* We plot the curve as if it is on a circle then stretch the points. This
+ * adjusts the angles so that when we stretch the points they will end in the
+ * right place. This is only complicated because atan and atan2 do not behave
+ * conveniently. */
+static void unstretch_angle(REAL * angle, REAL rad_x, REAL rad_y)
+{
+ REAL stretched;
+ INT revs_off;
+
+ *angle = deg2rad(*angle);
+
+ if(cos(*angle) == 0 || sin(*angle) == 0)
+ return;
+
+ stretched = atan2(sin(*angle) / rad_y, cos(*angle) / rad_x);
+ revs_off = roundr(*angle / (2.0 * M_PI)) - roundr(stretched / (2.0 * M_PI));
+ stretched += ((REAL)revs_off) * M_PI * 2.0;
+ *angle = stretched;
+}
+
+/* Stores the bezier points that correspond to the arc in points. If points is
+ * null, just return the number of points needed to represent the arc. */
+INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
+ REAL startAngle, REAL sweepAngle)
+{
+ INT i, count;
+ REAL end_angle, start_angle, endAngle;
+
+ endAngle = startAngle + sweepAngle;
+ unstretch_angle(&startAngle, x2 / 2.0, y2 / 2.0);
+ unstretch_angle(&endAngle, x2 / 2.0, y2 / 2.0);
+
+ count = ceilf(fabs(endAngle - startAngle) / M_PI_2) * 3 + 1;
+ /* don't make more than a full circle */
+ count = min(MAX_ARC_PTS, count);
+
+ if(count == 1)
+ return 0;
+ if(!points)
+ return count;
+
+ /* start_angle and end_angle are the iterative variables */
+ start_angle = startAngle;
+
+ for(i = 0; i < count - 1; i += 3){
+ /* check if we've overshot the end angle */
+ if( sweepAngle > 0.0 )
+ end_angle = min(start_angle + M_PI_2, endAngle);
+ else
+ end_angle = max(start_angle - M_PI_2, endAngle);
+
+ add_arc_part(&points[i], x1, y1, x2, y2, start_angle, end_angle, i == 0);
+
+ start_angle += M_PI_2 * (sweepAngle < 0.0 ? -1.0 : 1.0);
+ }
+
+ return count;
+}
diff --git a/dlls/gdiplus/gdiplus.spec b/dlls/gdiplus/gdiplus.spec
index 2d001ff..22b085e 100644
--- a/dlls/gdiplus/gdiplus.spec
+++ b/dlls/gdiplus/gdiplus.spec
@@ -1,4 +1,4 @@
-@ stub GdipAddPathArc
+@ stdcall GdipAddPathArc(ptr long long long long long long)
@ stub GdipAddPathArcI
@ stub GdipAddPathBezier
@ stub GdipAddPathBezierI
diff --git a/dlls/gdiplus/gdiplus_private.h b/dlls/gdiplus/gdiplus_private.h
index 2bf3b5b..7278b22 100644
--- a/dlls/gdiplus/gdiplus_private.h
+++ b/dlls/gdiplus/gdiplus_private.h
@@ -23,10 +23,13 @@ #include "windef.h"
#include "gdiplus.h"
#define GP_DEFAULT_PENSTYLE (PS_GEOMETRIC | PS_ENDCAP_FLAT | PS_JOIN_MITER)
+#define MAX_ARC_PTS (13)
extern COLORREF ARGB2COLORREF(ARGB color);
extern INT roundr(REAL x);
extern REAL deg2rad(REAL degrees);
+extern INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
+ REAL startAngle, REAL sweepAngle);
struct GpPen{
UINT style;
diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c
index 5df628d..e65dabd 100644
--- a/dlls/gdiplus/graphicspath.c
+++ b/dlls/gdiplus/graphicspath.c
@@ -63,6 +63,37 @@ static BOOL lengthen_path(GpPath *path,
return TRUE;
}
+GpStatus WINGDIPAPI GdipAddPathArc(GpPath *path, REAL x1, REAL y1, REAL x2,
+ REAL y2, REAL startAngle, REAL sweepAngle)
+{
+ INT count, old_count, i;
+
+ if(!path)
+ return InvalidParameter;
+
+ count = arc2polybezier(NULL, x1, y1, x2, y2, startAngle, sweepAngle);
+
+ if(count == 0)
+ return Ok;
+ if(!lengthen_path(path, count))
+ return OutOfMemory;
+
+ old_count = path->pathdata.Count;
+ arc2polybezier(&path->pathdata.Points[old_count], x1, y1, x2, y2,
+ startAngle, sweepAngle);
+
+ for(i = 0; i < count; i++){
+ path->pathdata.Types[old_count + i] = PathPointTypeBezier;
+ }
+
+ path->pathdata.Types[old_count] =
+ (path->newfigure ? PathPointTypeStart : PathPointTypeLine);
+ path->newfigure = FALSE;
+ path->pathdata.Count += count;
+
+ return Ok;
+}
+
GpStatus WINGDIPAPI GdipAddPathLine2(GpPath *path, GDIPCONST GpPointF *points,
INT count)
{
diff --git a/include/gdiplusflat.h b/include/gdiplusflat.h
index d9f5f9a..e49ecc3 100644
--- a/include/gdiplusflat.h
+++ b/include/gdiplusflat.h
@@ -48,6 +48,7 @@ GpStatus WINGDIPAPI GdipCreateSolidFill(
GpStatus WINGDIPAPI GdipGetBrushType(GpBrush*,GpBrushType*);
GpStatus WINGDIPAPI GdipDeleteBrush(GpBrush*);
+GpStatus WINGDIPAPI GdipAddPathArc(GpPath*,REAL,REAL,REAL,REAL,REAL,REAL);
GpStatus WINGDIPAPI GdipAddPathLine2(GpPath*,GDIPCONST GpPointF*,INT);
GpStatus WINGDIPAPI GdipClosePathFigure(GpPath*);
GpStatus WINGDIPAPI GdipClosePathFigures(GpPath*);
--
1.4.1
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