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fix angles by flipping the coordinate system back to its original y

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2007-06-10  Michael Natterer  <mitch@imendio.com>

	* gdk/quartz/gdkdrawable-quartz.c (gdk_quartz_draw_arc): fix
	angles by flipping the coordinate system back to its original y
	direction. The implementtion is still broken for ellipses, will
	have to simulate them using bezier curves.


svn path=/trunk/; revision=18095
This commit is contained in:
Michael Natterer 2007-06-10 16:29:31 +00:00 committed by Michael Natterer
parent 83d5a36c9f
commit f7ba83c613
2 changed files with 32 additions and 6 deletions
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7
ChangeLog
View File

@ -1,3 +1,10 @@
2007-06-10 Michael Natterer <mitch@imendio.com>
* gdk/quartz/gdkdrawable-quartz.c (gdk_quartz_draw_arc): fix
angles by flipping the coordinate system back to its original y
direction. The implementtion is still broken for ellipses, will
have to simulate them using bezier curves.
2007-06-10 Cody Russell <bratsche@gnome.org> 2007-06-10 Cody Russell <bratsche@gnome.org>
* gdk/win32/gdkevents-win32.c (gdk_pointer_grab): * gdk/win32/gdkevents-win32.c (gdk_pointer_grab):

31
gdk/quartz/gdkdrawable-quartz.c
View File

@ -173,6 +173,7 @@ gdk_quartz_draw_arc (GdkDrawable *drawable,
{ {
CGContextRef context = gdk_quartz_drawable_get_context (drawable, FALSE); CGContextRef context = gdk_quartz_drawable_get_context (drawable, FALSE);
float start_angle, end_angle; float start_angle, end_angle;
gboolean clockwise = FALSE;
if (!context) if (!context)
return; return;
@ -184,20 +185,38 @@ gdk_quartz_draw_arc (GdkDrawable *drawable,
CGContextSaveGState (context); CGContextSaveGState (context);
start_angle = (2 - (angle1 / (180.0 * 64.0))) * G_PI; start_angle = angle1 * 2.0 * G_PI / 360.0 / 64.0;
end_angle = start_angle - (angle2 / (180.0 * 64.0)) * G_PI; end_angle = start_angle + angle2 * 2.0 * G_PI / 360.0 / 64.0;
/* angle2 is relative to angle1 and can be negative, which switches
* the drawing direction
*/
if (angle2 < 0)
clockwise = TRUE;
/* below, flip the coordinate system back to its original y-diretion
* so the angles passed to CGContextAddArc() are interpreted as
* expected
*
* FIXME: the implementation below works only for perfect circles
* (width == height). Any other aspect ratio either scales the
* line width unevenly or scales away the path entirely for very
* small line widths (esp. for line_width == 0, which is a hair
* line on X11 but must be approximated with the thinnest possible
* line on quartz).
*/
if (filled) if (filled)
{ {
CGContextTranslateCTM (context, CGContextTranslateCTM (context,
x + width / 2.0, x + width / 2.0,
y + height / 2.0); y + height / 2.0);
CGContextScaleCTM (context, 1.0, (double)height / (double)width); CGContextScaleCTM (context, 1.0, - (double)height / (double)width);
CGContextMoveToPoint (context, 0, 0); CGContextMoveToPoint (context, 0, 0);
CGContextAddArc (context, 0, 0, width / 2.0, CGContextAddArc (context, 0, 0, width / 2.0,
start_angle, end_angle, start_angle, end_angle,
TRUE); clockwise);
CGContextClosePath (context); CGContextClosePath (context);
CGContextFillPath (context); CGContextFillPath (context);
} }
@ -206,11 +225,11 @@ gdk_quartz_draw_arc (GdkDrawable *drawable,
CGContextTranslateCTM (context, CGContextTranslateCTM (context,
x + width / 2.0 + 0.5, x + width / 2.0 + 0.5,
y + height / 2.0 + 0.5); y + height / 2.0 + 0.5);
CGContextScaleCTM (context, 1.0, (double)height / (double)width); CGContextScaleCTM (context, 1.0, - (double)height / (double)width);
CGContextAddArc (context, 0, 0, width / 2.0, CGContextAddArc (context, 0, 0, width / 2.0,
start_angle, end_angle, start_angle, end_angle,
TRUE); clockwise);
CGContextStrokePath (context); CGContextStrokePath (context);
} }