libui/haiku/draw.cpp

408 lines
8.6 KiB
C++

// 19 november 2015
#include <cmath>
#include "uipriv_haiku.hpp"
using namespace std;
struct uiDrawPath {
BShape *shape;
uiDrawFillMode fillMode;
bool ended;
};
uiDrawPath *uiDrawNewPath(uiDrawFillMode fillMode)
{
uiDrawPath *p;
p = uiNew(uiDrawPath);
p->shape = new BShape();
p->fillMode = fillMode;
return p;
}
void uiDrawFreePath(uiDrawPath *p)
{
delete p->shape;
uiFree(p);
}
// TODO add ended checks
// TODO add error checks
void uiDrawPathNewFigure(uiDrawPath *p, double x, double y)
{
p->shape->MoveTo(BPoint(x, y));
}
// Even though BView::FillArc()/StrokeArc() existed and used the sane arc drawing model, Haiku decided to use the Direct2D arc drawing model when it added BShape::ArcTo().
// So refer to windows/draw.c for details.
// This is slightly better as it uses center points and sweep amounts instead of endpoints, but *still*.
// TODO split into common/d2darc.c
struct arc {
double xCenter;
double yCenter;
double radius;
double startAngle;
double sweep;
int negative;
};
// this is used for the comparison below
// if it falls apart it can be changed later
#define aerMax 6 * DBL_EPSILON
static void drawArc(uiDrawPath *p, struct arc *a, void (*startFunction)(uiDrawPath *, double, double))
{
double sinx, cosx;
double startX, startY;
double endX, endY;
bool largeArc;
bool counterclockwise;
bool fullCircle;
double absSweep;
// TODO is this relevaith Haiku?
// as above, we can't do a full circle with one arc
// simulate it with two half-circles
// of course, we have a dragon: equality on floating-point values!
// I've chosen to do the AlmostEqualRelative() technique in https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
fullCircle = false;
// use the absolute value to tackle both ≥2π and ≤-2π at the same time
absSweep = fabs(a->sweep);
if (absSweep > (2 * M_PI)) // this part is easy
fullCircle = true;
else {
double aerDiff;
aerDiff = fabs(absSweep - (2 * M_PI));
// if we got here then we know a->sweep is larger (or the same!)
fullCircle = aerDiff <= absSweep * aerMax;
}
// TODO make sure this works right for the negative direction
if (fullCircle) {
a->sweep = M_PI;
drawArc(p, a, startFunction);
a->startAngle += M_PI;
drawArc(p, a, NULL);
return;
}
// first, figure out the arc's endpoints
sinx = sin(a->startAngle);
cosx = cos(a->startAngle);
startX = a->xCenter + a->radius * cosx;
startY = a->yCenter + a->radius * sinx;
sinx = sin(a->startAngle + a->sweep);
cosx = cos(a->startAngle + a->sweep);
endX = a->xCenter + a->radius * cosx;
endY = a->yCenter + a->radius * sinx;
// now do the initial step to get the current point to be the start point
// this is either creating a new figure, drawing a line, or (in the case of our full circle code above) doing nothing
if (startFunction != NULL)
(*startFunction)(p, startX, startY);
// now we can draw the arc
if (a->negative)
counterclockwise = true;
else
counterclockwise = false;
// TODO explain the outer if
if (!a->negative)
if (a->sweep > M_PI)
largeArc = true;
else
largeArc = false;
else
// TODO especially this part
if (a->sweep > M_PI)
largeArc = false;
else
largeArc = true;
p->shape->ArcTo(a->radius, a->radius,
// TODO should this be sweep amount?
a->startAngle, // TODO convert to degrees
largeArc, counterclockwise,
BPoint(a->xCenter, a->yCenter));
}
void uiDrawPathNewFigureWithArc(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative)
{
struct arc a;
a.xCenter = xCenter;
a.yCenter = yCenter;
a.radius = radius;
a.startAngle = startAngle;
a.sweep = sweep;
a.negative = negative;
drawArc(p, &a, uiDrawPathNewFigure);
}
void uiDrawPathLineTo(uiDrawPath *p, double x, double y)
{
p->shape->LineTo(BPoint(x, y));
}
void uiDrawPathArcTo(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative)
{
struct arc a;
a.xCenter = xCenter;
a.yCenter = yCenter;
a.radius = radius;
a.startAngle = startAngle;
a.sweep = sweep;
a.negative = negative;
drawArc(p, &a, uiDrawPathLineTo);
}
void uiDrawPathBezierTo(uiDrawPath *p, double c1x, double c1y, double c2x, double c2y, double endX, double endY)
{
p->shape->BezierTo(BPoint(c1x, c1y),
BPoint(c2x, c2y),
BPoint(endX, endY));
}
void uiDrawPathCloseFigure(uiDrawPath *p)
{
p->shape->Close();
}
void uiDrawPathAddRectangle(uiDrawPath *p, double x, double y, double width, double height)
{
// this is the same algorithm used by cairo and Core Graphics, according to their documentations
uiDrawPathNewFigure(p, x, y);
uiDrawPathLineTo(p, x + width, y);
uiDrawPathLineTo(p, x + width, y + height);
uiDrawPathLineTo(p, x, y + height);
uiDrawPathCloseFigure(p);
}
void uiDrawPathEnd(uiDrawPath *p)
{
p->ended = true;
}
struct uiDrawContext {
BView *view;
};
uiDrawContext *newContext(BView *view)
{
uiDrawContext *c;
c = uiNew(uiDrawContext);
c->view = view;
return c;
}
void freeContext(uiDrawContext *c)
{
uiFree(c);
}
// TODO verify this
static void setHighColor(BView *view, uiDrawBrush *b)
{
view->SetHighColor(b->R * 255,
b->G * 255,
b->B * 255,
b->A * 255);
}
// TODO path ended checks; error checks
void uiDrawStroke(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b, uiDrawStrokeParams *p)
{
cap_mode cap;
join_mode join;
switch (p->Cap) {
case uiDrawLineCapFlat:
cap = B_BUTT_CAP;
break;
case uiDrawLineCapRound:
cap = B_ROUND_CAP;
break;
case uiDrawLineCapSquare:
cap = B_SQUARE_CAP;
break;
}
switch (p->Join) {
case uiDrawLineJoinMiter:
join = B_MITER_JOIN;
break;
case uiDrawLineJoinRound:
join = B_ROUND_JOIN;
break;
case uiDrawLineJoinBevel:
join = B_BEVEL_JOIN;
break;
}
c->view->SetLineMode(cap, join, p->MiterLimit);
c->view->SetPenSize(p->Thickness);
// TODO line dashes
switch (b->Type) {
case uiDrawBrushTypeSolid:
setHighColor(c->view, b);
c->view->StrokeShape(path->shape);
break;
case uiDrawBrushTypeLinearGradient:
// TODO
case uiDrawBrushTypeRadialGradient:
// TODO
break;
// case uiDrawBrushTypeImage:
}
}
void uiDrawFill(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b)
{
// TODO not documented on api.haiku-os.org
switch (path->fillMode) {
case uiDrawFillModeWinding:
c->view->SetFillRule(B_NONZERO);
break;
case uiDrawFillModeAlternate:
c->view->SetFillRule(B_EVEN_ODD);
break;
}
switch (b->Type) {
case uiDrawBrushTypeSolid:
setHighColor(c->view, b);
c->view->FillShape(path->shape);
break;
case uiDrawBrushTypeLinearGradient:
// TODO
case uiDrawBrushTypeRadialGradient:
// TODO
break;
// case uiDrawBrushTypeImage:
}
}
// TODO none of this is documented on api.haiku-os.org
static void m2a(uiDrawMatrix *m, BAffineTransform *a)
{
a->sx = m->M11;
a->shy = m->M12;
a->shx = m->M21;
a->sy = m->M22;
a->tx = m->M31;
a->ty = m->M32;
}
static void a2m(BAffineTransform *a, uiDrawMatrix *m)
{
m->M11 = a->sx;
m->M12 = a->shy;
m->M21 = a->shx;
m->M22 = a->sy;
m->M31 = a->tx;
m->M32 = a->ty;
}
void uiDrawMatrixSetIdentity(uiDrawMatrix *m)
{
setIdentity(m);
}
void uiDrawMatrixTranslate(uiDrawMatrix *m, double x, double y)
{
BAffineTransform a;
m2a(m, &a);
a.TranslateBy(x, y);
a2m(&a, m);
}
void uiDrawMatrixScale(uiDrawMatrix *m, double xCenter, double yCenter, double x, double y)
{
BAffineTransform a;
m2a(m, &a);
a.ScaleBy(BPoint(xCenter, yCenter), BPoint(x, y));
a2m(&a, m);
}
void uiDrawMatrixRotate(uiDrawMatrix *m, double x, double y, double amount)
{
BAffineTransform a;
m2a(m, &a);
// TODO degrees or radians?
a.RotateBy(BPoint(x, y), amount);
a2m(&a, m);
}
void uiDrawMatrixSkew(uiDrawMatrix *m, double x, double y, double xamount, double yamount)
{
BAffineTransform a;
m2a(m, &a);
// TODO degrees or radians?
a.ShearBy(BPoint(x, y), BPoint(xamount, yamount));
a2m(&a, m);
}
void uiDrawMatrixMultiply(uiDrawMatrix *dest, uiDrawMatrix *src)
{
BAffineTransform c;
BAffineTransform d;
m2a(dest, &c);
m2a(src, &d);
c.Multiply(d);
a2m(&c, dest);
}
int uiDrawMatrixInvertible(uiDrawMatrix *m)
{
// TODO
return 0;
}
int uiDrawMatrixInvert(uiDrawMatrix *m)
{
// TODO
return 0;
}
void uiDrawMatrixTransformPoint(uiDrawMatrix *m, double *x, double *y)
{
// TODO
}
void uiDrawMatrixTransformSize(uiDrawMatrix *m, double *x, double *y)
{
// TODO
}
void uiDrawTransform(uiDrawContext *c, uiDrawMatrix *m)
{
BAffineTransform a;
m2a(m, &a);
// see windows/draw.c
a.Multiply(c->view->Transform());
c->view->SetTransform(a);
}
// TODO not documented on api.haiku-os.org
void uiDrawClip(uiDrawContext *c, uiDrawPath *path)
{
c->view->ClipToShape(path->shape);
}
void uiDrawSave(uiDrawContext *c)
{
c->view->PushState();
}
void uiDrawRestore(uiDrawContext *c)
{
c->view->PopState();
}