interesting
/
libui
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Got the Windows backend's arc code mostly working. It's still 360° arcs that cause problems...

This commit is contained in:
Pietro Gagliardi 2015-10-10 09:23:44 -04:00
parent 3fad1a16d7
commit 22b38accee
1 changed files with 7 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
windows/draw.c
View File

@ -137,14 +137,14 @@ static void arcEndpoint(double xCenter, double yCenter, double radius, double st
sinStart = sin(startAngle);
cosStart = cos(startAngle);
*startX = xCenter + radius * cosStart;
*startY = yCenter + radius * sinStart;
*startY = yCenter - radius * sinStart;
}
// An arc in Direct2D is defined by the chord between its endpoints, not solely by the sweep angle.
// There are four possible arcs with the same sweep amount that you can draw this way.
// See https://www.youtube.com/watch?v=ATS0ANW1UxQ for a demonstration.
// TODO stress test this, compare to cairo and Core Graphics; handle the case where sweep >= 2π
static void doDrawArc(ID2D1GeometrySink *sink, double startX, double startY, double endX, double endY, double radius, double sweep)
// TODO clean this up, document it better, and merge it with the above and below functions
static void doDrawArc(ID2D1GeometrySink *sink, double endX, double endY, double radius, double sweep)
{
D2D1_ARC_SEGMENT as;
@ -155,12 +155,8 @@ static void doDrawArc(ID2D1GeometrySink *sink, double startX, double startY, dou
as.size.width = radius;
as.size.height = radius;
as.rotationAngle = sweep * (180.0 / M_PI);
// TODO explain this
if (sweep < 0)
as.sweepDirection = D2D1_SWEEP_DIRECTION_COUNTER_CLOCKWISE;
else
as.sweepDirection = D2D1_SWEEP_DIRECTION_CLOCKWISE;
if (fabs(sweep) > M_PI)
as.sweepDirection = D2D1_SWEEP_DIRECTION_COUNTER_CLOCKWISE;
if (sweep > M_PI)
as.arcSize = D2D1_ARC_SIZE_LARGE;
else
as.arcSize = D2D1_ARC_SIZE_SMALL;
@ -178,7 +174,7 @@ void uiDrawPathNewFigureWithArc(uiDrawPath *p, double xCenter, double yCenter, d
// draw the arc
arcEndpoint(xCenter, yCenter, radius, startAngle + sweep, &endX, &endY);
doDrawArc(p->sink, startX, startY, endX, endY, radius, sweep);
doDrawArc(p->sink, endX, endY, radius, sweep);
}
void uiDrawPathLineTo(uiDrawPath *p, double x, double y)
@ -201,7 +197,7 @@ void uiDrawPathArcTo(uiDrawPath *p, double xCenter, double yCenter, double radiu
// draw the arc
arcEndpoint(xCenter, yCenter, radius, startAngle + sweep, &endX, &endY);
doDrawArc(p->sink, startX, startY, endX, endY, radius, sweep);
doDrawArc(p->sink, endX, endY, radius, sweep);
}
void uiDrawPathBezierTo(uiDrawPath *p, double c1x, double c1y, double c2x, double c2y, double endX, double endY)