libui/darwin/draw.m

451 lines
11 KiB
Objective-C

// 6 september 2015
#import "uipriv_darwin.h"
#import "draw.h"
struct uiDrawPath {
CGMutablePathRef path;
uiDrawFillMode fillMode;
BOOL ended;
};
uiDrawPath *uiDrawNewPath(uiDrawFillMode mode)
{
uiDrawPath *p;
p = uiNew(uiDrawPath);
p->path = CGPathCreateMutable();
p->fillMode = mode;
return p;
}
void uiDrawFreePath(uiDrawPath *p)
{
CGPathRelease((CGPathRef) (p->path));
uiFree(p);
}
void uiDrawPathNewFigure(uiDrawPath *p, double x, double y)
{
if (p->ended)
userbug("You cannot call uiDrawPathNewFigure() on a uiDrawPath that has already been ended. (path; %p)", p);
CGPathMoveToPoint(p->path, NULL, x, y);
}
void uiDrawPathNewFigureWithArc(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative)
{
double sinStart, cosStart;
double startx, starty;
if (p->ended)
userbug("You cannot call uiDrawPathNewFigureWithArc() on a uiDrawPath that has already been ended. (path; %p)", p);
sinStart = sin(startAngle);
cosStart = cos(startAngle);
startx = xCenter + radius * cosStart;
starty = yCenter + radius * sinStart;
CGPathMoveToPoint(p->path, NULL, startx, starty);
uiDrawPathArcTo(p, xCenter, yCenter, radius, startAngle, sweep, negative);
}
void uiDrawPathLineTo(uiDrawPath *p, double x, double y)
{
// TODO refine this to require being in a path
if (p->ended)
implbug("attempt to add line to ended path in uiDrawPathLineTo()");
CGPathAddLineToPoint(p->path, NULL, x, y);
}
void uiDrawPathArcTo(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative)
{
bool cw;
// TODO likewise
if (p->ended)
implbug("attempt to add arc to ended path in uiDrawPathArcTo()");
if (sweep > 2 * uiPi)
sweep = 2 * uiPi;
cw = false;
if (negative)
cw = true;
CGPathAddArc(p->path, NULL,
xCenter, yCenter,
radius,
startAngle, startAngle + sweep,
cw);
}
void uiDrawPathBezierTo(uiDrawPath *p, double c1x, double c1y, double c2x, double c2y, double endX, double endY)
{
// TODO likewise
if (p->ended)
implbug("attempt to add bezier to ended path in uiDrawPathBezierTo()");
CGPathAddCurveToPoint(p->path, NULL,
c1x, c1y,
c2x, c2y,
endX, endY);
}
void uiDrawPathCloseFigure(uiDrawPath *p)
{
// TODO likewise
if (p->ended)
implbug("attempt to close figure of ended path in uiDrawPathCloseFigure()");
CGPathCloseSubpath(p->path);
}
void uiDrawPathAddRectangle(uiDrawPath *p, double x, double y, double width, double height)
{
if (p->ended)
userbug("You cannot call uiDrawPathAddRectangle() on a uiDrawPath that has already been ended. (path; %p)", p);
CGPathAddRect(p->path, NULL, CGRectMake(x, y, width, height));
}
void uiDrawPathEnd(uiDrawPath *p)
{
p->ended = TRUE;
}
uiDrawContext *newContext(CGContextRef ctxt, CGFloat height)
{
uiDrawContext *c;
c = uiNew(uiDrawContext);
c->c = ctxt;
c->height = height;
return c;
}
void freeContext(uiDrawContext *c)
{
uiFree(c);
}
// a stroke is identical to a fill of a stroked path
// we need to do this in order to stroke with a gradient; see http://stackoverflow.com/a/25034854/3408572
// doing this for other brushes works too
void uiDrawStroke(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b, uiDrawStrokeParams *p)
{
CGLineCap cap;
CGLineJoin join;
CGPathRef dashPath;
CGFloat *dashes;
size_t i;
uiDrawPath p2;
if (!path->ended)
userbug("You cannot call uiDrawStroke() on a uiDrawPath that has not been ended. (path: %p)", path);
switch (p->Cap) {
case uiDrawLineCapFlat:
cap = kCGLineCapButt;
break;
case uiDrawLineCapRound:
cap = kCGLineCapRound;
break;
case uiDrawLineCapSquare:
cap = kCGLineCapSquare;
break;
}
switch (p->Join) {
case uiDrawLineJoinMiter:
join = kCGLineJoinMiter;
break;
case uiDrawLineJoinRound:
join = kCGLineJoinRound;
break;
case uiDrawLineJoinBevel:
join = kCGLineJoinBevel;
break;
}
// create a temporary path identical to the previous one
dashPath = (CGPathRef) path->path;
if (p->NumDashes != 0) {
dashes = (CGFloat *) uiAlloc(p->NumDashes * sizeof (CGFloat), "CGFloat[]");
for (i = 0; i < p->NumDashes; i++)
dashes[i] = p->Dashes[i];
dashPath = CGPathCreateCopyByDashingPath(path->path,
NULL,
p->DashPhase,
dashes,
p->NumDashes);
uiFree(dashes);
}
// the documentation is wrong: this produces a path suitable for calling CGPathCreateCopyByStrokingPath(), not for filling directly
// the cast is safe; we never modify the CGPathRef and always cast it back to a CGPathRef anyway
p2.path = (CGMutablePathRef) CGPathCreateCopyByStrokingPath(dashPath,
NULL,
p->Thickness,
cap,
join,
p->MiterLimit);
if (p->NumDashes != 0)
CGPathRelease(dashPath);
// always draw stroke fills using the winding rule
// otherwise intersecting figures won't draw correctly
p2.fillMode = uiDrawFillModeWinding;
p2.ended = path->ended;
uiDrawFill(c, &p2, b);
// and clean up
CGPathRelease((CGPathRef) (p2.path));
}
// for a solid fill, we can merely have Core Graphics fill directly
static void fillSolid(CGContextRef ctxt, uiDrawPath *p, uiDrawBrush *b)
{
// TODO this uses DeviceRGB; switch to sRGB
CGContextSetRGBFillColor(ctxt, b->R, b->G, b->B, b->A);
switch (p->fillMode) {
case uiDrawFillModeWinding:
CGContextFillPath(ctxt);
break;
case uiDrawFillModeAlternate:
CGContextEOFillPath(ctxt);
break;
}
}
// for a gradient fill, we need to clip to the path and then draw the gradient
// see http://stackoverflow.com/a/25034854/3408572
static void fillGradient(CGContextRef ctxt, uiDrawPath *p, uiDrawBrush *b)
{
CGGradientRef gradient;
CGColorSpaceRef colorspace;
CGFloat *colors;
CGFloat *locations;
size_t i;
// gradients need a color space
// for consistency with windows, use sRGB
colorspace = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
// make the gradient
colors = uiAlloc(b->NumStops * 4 * sizeof (CGFloat), "CGFloat[]");
locations = uiAlloc(b->NumStops * sizeof (CGFloat), "CGFloat[]");
for (i = 0; i < b->NumStops; i++) {
colors[i * 4 + 0] = b->Stops[i].R;
colors[i * 4 + 1] = b->Stops[i].G;
colors[i * 4 + 2] = b->Stops[i].B;
colors[i * 4 + 3] = b->Stops[i].A;
locations[i] = b->Stops[i].Pos;
}
gradient = CGGradientCreateWithColorComponents(colorspace, colors, locations, b->NumStops);
uiFree(locations);
uiFree(colors);
// because we're mucking with clipping, we need to save the graphics state and restore it later
CGContextSaveGState(ctxt);
// clip
switch (p->fillMode) {
case uiDrawFillModeWinding:
CGContextClip(ctxt);
break;
case uiDrawFillModeAlternate:
CGContextEOClip(ctxt);
break;
}
// draw the gradient
switch (b->Type) {
case uiDrawBrushTypeLinearGradient:
CGContextDrawLinearGradient(ctxt,
gradient,
CGPointMake(b->X0, b->Y0),
CGPointMake(b->X1, b->Y1),
kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
break;
case uiDrawBrushTypeRadialGradient:
CGContextDrawRadialGradient(ctxt,
gradient,
CGPointMake(b->X0, b->Y0),
// make the start circle radius 0 to make it a point
0,
CGPointMake(b->X1, b->Y1),
b->OuterRadius,
kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
break;
}
// and clean up
CGContextRestoreGState(ctxt);
CGGradientRelease(gradient);
CGColorSpaceRelease(colorspace);
}
void uiDrawFill(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b)
{
if (!path->ended)
userbug("You cannot call uiDrawStroke() on a uiDrawPath that has not been ended. (path: %p)", path);
CGContextAddPath(c->c, (CGPathRef) (path->path));
switch (b->Type) {
case uiDrawBrushTypeSolid:
fillSolid(c->c, path, b);
return;
case uiDrawBrushTypeLinearGradient:
case uiDrawBrushTypeRadialGradient:
fillGradient(c->c, path, b);
return;
// case uiDrawBrushTypeImage:
// TODO
return;
}
userbug("Unknown brush type %d passed to uiDrawFill().", b->Type);
}
static void m2c(uiDrawMatrix *m, CGAffineTransform *c)
{
c->a = m->M11;
c->b = m->M12;
c->c = m->M21;
c->d = m->M22;
c->tx = m->M31;
c->ty = m->M32;
}
static void c2m(CGAffineTransform *c, uiDrawMatrix *m)
{
m->M11 = c->a;
m->M12 = c->b;
m->M21 = c->c;
m->M22 = c->d;
m->M31 = c->tx;
m->M32 = c->ty;
}
void uiDrawMatrixTranslate(uiDrawMatrix *m, double x, double y)
{
CGAffineTransform c;
m2c(m, &c);
c = CGAffineTransformTranslate(c, x, y);
c2m(&c, m);
}
void uiDrawMatrixScale(uiDrawMatrix *m, double xCenter, double yCenter, double x, double y)
{
CGAffineTransform c;
double xt, yt;
m2c(m, &c);
xt = x;
yt = y;
scaleCenter(xCenter, yCenter, &xt, &yt);
c = CGAffineTransformTranslate(c, xt, yt);
c = CGAffineTransformScale(c, x, y);
c = CGAffineTransformTranslate(c, -xt, -yt);
c2m(&c, m);
}
void uiDrawMatrixRotate(uiDrawMatrix *m, double x, double y, double amount)
{
CGAffineTransform c;
m2c(m, &c);
c = CGAffineTransformTranslate(c, x, y);
c = CGAffineTransformRotate(c, amount);
c = CGAffineTransformTranslate(c, -x, -y);
c2m(&c, m);
}
void uiDrawMatrixSkew(uiDrawMatrix *m, double x, double y, double xamount, double yamount)
{
fallbackSkew(m, x, y, xamount, yamount);
}
void uiDrawMatrixMultiply(uiDrawMatrix *dest, uiDrawMatrix *src)
{
CGAffineTransform c;
CGAffineTransform d;
m2c(dest, &c);
m2c(src, &d);
c = CGAffineTransformConcat(c, d);
c2m(&c, dest);
}
// there is no test for invertibility; CGAffineTransformInvert() is merely documented as returning the matrix unchanged if it isn't invertible
// therefore, special care must be taken to catch matrices who are their own inverses
// TODO figure out which matrices these are and do so
int uiDrawMatrixInvertible(uiDrawMatrix *m)
{
CGAffineTransform c, d;
m2c(m, &c);
d = CGAffineTransformInvert(c);
return CGAffineTransformEqualToTransform(c, d) == false;
}
int uiDrawMatrixInvert(uiDrawMatrix *m)
{
CGAffineTransform c, d;
m2c(m, &c);
d = CGAffineTransformInvert(c);
if (CGAffineTransformEqualToTransform(c, d))
return 0;
c2m(&d, m);
return 1;
}
void uiDrawMatrixTransformPoint(uiDrawMatrix *m, double *x, double *y)
{
CGAffineTransform c;
CGPoint p;
m2c(m, &c);
p = CGPointApplyAffineTransform(CGPointMake(*x, *y), c);
*x = p.x;
*y = p.y;
}
void uiDrawMatrixTransformSize(uiDrawMatrix *m, double *x, double *y)
{
CGAffineTransform c;
CGSize s;
m2c(m, &c);
s = CGSizeApplyAffineTransform(CGSizeMake(*x, *y), c);
*x = s.width;
*y = s.height;
}
void uiDrawTransform(uiDrawContext *c, uiDrawMatrix *m)
{
CGAffineTransform cm;
m2c(m, &cm);
CGContextConcatCTM(c->c, cm);
}
void uiDrawClip(uiDrawContext *c, uiDrawPath *path)
{
if (!path->ended)
userbug("You cannot call uiDrawCilp() on a uiDrawPath that has not been ended. (path: %p)", path);
CGContextAddPath(c->c, (CGPathRef) (path->path));
switch (path->fillMode) {
case uiDrawFillModeWinding:
CGContextClip(c->c);
break;
case uiDrawFillModeAlternate:
CGContextEOClip(c->c);
break;
}
}
// TODO figure out what besides transforms these save/restore on all platforms
void uiDrawSave(uiDrawContext *c)
{
CGContextSaveGState(c->c);
}
void uiDrawRestore(uiDrawContext *c)
{
CGContextRestoreGState(c->c);
}
void uiDrawText(uiDrawContext *c, double x, double y, uiDrawTextLayout *layout)
{
doDrawText(c->c, c->height, x, y, layout);
}