sw_engine: fix trimming

For the 'simultaneous' trimming option, the maximum
stroke length from all subpaths was determined and
used to scale the trim of each subpath. As a result,
if the subpaths had different lengths, this scaling
was incorrect.
Now, the length is determined separately for each
subpath and is used to scale the trimming of its stroke.

@Issue: https://github.com/thorvg/thorvg/issues/2335
This commit is contained in:
Mira Grudzinska 2024-06-05 12:30:19 +02:00 committed by Hermet Park
parent 97a1aa136a
commit 07e386007c

View file

@ -245,7 +245,86 @@ static void _dashMoveTo(SwDashStroke& dash, uint32_t offIdx, float offset, const
}
static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* transform, float length, SwMpool* mpool, unsigned tid)
static void _trimPattern(SwDashStroke* dash, const RenderShape* rshape, float length)
{
auto begin = length * rshape->stroke->trim.begin;
auto end = length * rshape->stroke->trim.end;
//default
if (end > begin) {
if (begin > 0.0f) dash->cnt = 4;
else dash->cnt = 2;
//looping
} else dash->cnt = 3;
if (dash->cnt == 2) {
dash->pattern[0] = end - begin;
dash->pattern[1] = length - (end - begin);
} else if (dash->cnt == 3) {
dash->pattern[0] = end;
dash->pattern[1] = (begin - end);
dash->pattern[2] = length - begin;
} else {
dash->pattern[0] = 0; //zero dash to start with a space.
dash->pattern[1] = begin;
dash->pattern[2] = end - begin;
dash->pattern[3] = length - end;
}
}
static float _outlineLength(const RenderShape* rshape, uint32_t shiftPts, uint32_t shiftCmds, bool subpath)
{
const PathCommand* cmds = rshape->path.cmds.data + shiftCmds;
auto cmdCnt = rshape->path.cmds.count - shiftCmds;
const Point* pts = rshape->path.pts.data + shiftPts;
auto ptsCnt = rshape->path.pts.count - shiftPts;
//No actual shape data
if (cmdCnt <= 0 || ptsCnt <= 0) return 0.0f;
const Point* close = nullptr;
auto length = 0.0f;
//must begin with moveTo
if (cmds[0] == PathCommand::MoveTo) {
close = pts;
cmds++;
pts++;
cmdCnt--;
}
while (cmdCnt-- > 0) {
switch (*cmds) {
case PathCommand::Close: {
length += mathLength(pts - 1, close);
if (subpath) return length;
break;
}
case PathCommand::MoveTo: {
if (subpath) return length;
close = pts;
++pts;
break;
}
case PathCommand::LineTo: {
length += mathLength(pts - 1, pts);
++pts;
break;
}
case PathCommand::CubicTo: {
length += bezLength({*(pts - 1), *pts, *(pts + 1), *(pts + 2)});
pts += 3;
break;
}
}
++cmds;
}
return length;
}
static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* transform, bool trimmed, SwMpool* mpool, unsigned tid)
{
const PathCommand* cmds = rshape->path.cmds.data;
auto cmdCnt = rshape->path.cmds.count;
@ -255,49 +334,23 @@ static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* trans
//No actual shape data
if (cmdCnt == 0 || ptsCnt == 0) return nullptr;
auto startPts = pts;
auto startCmds = cmds;
SwDashStroke dash;
auto offset = 0.0f;
auto trimmed = false;
dash.cnt = rshape->strokeDash((const float**)&dash.pattern, &offset);
auto simultaneous = rshape->stroke->trim.simultaneous;
//dash by trimming.
if (length > 0.0f && dash.cnt == 0) {
auto begin = length * rshape->stroke->trim.begin;
auto end = length * rshape->stroke->trim.end;
//TODO: mix trimming + dash style
//default
if (end > begin) {
if (begin > 0.0f) dash.cnt += 4;
else dash.cnt += 2;
//looping
} else dash.cnt += 3;
dash.pattern = (float*)malloc(sizeof(float) * dash.cnt);
if (dash.cnt == 2) {
dash.pattern[0] = end - begin;
dash.pattern[1] = length - (end - begin);
} else if (dash.cnt == 3) {
dash.pattern[0] = end;
dash.pattern[1] = (begin - end);
dash.pattern[2] = length - begin;
if (dash.cnt == 0) {
if (trimmed) dash.pattern = (float*)malloc(sizeof(float) * 4);
else return nullptr;
} else {
dash.pattern[0] = 0; //zero dash to start with a space.
dash.pattern[1] = begin;
dash.pattern[2] = end - begin;
dash.pattern[3] = length - end;
//TODO: handle dash + trim - for now trimming ignoring is forced
trimmed = false;
}
trimmed = true;
//just a dasy style.
} else {
if (dash.cnt == 0) return nullptr;
}
//offset?
//offset
auto patternLength = 0.0f;
uint32_t offIdx = 0;
if (!mathZero(offset)) {
@ -319,6 +372,7 @@ static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* trans
//must begin with moveTo
if (cmds[0] == PathCommand::MoveTo) {
if (trimmed) _trimPattern(&dash, rshape, _outlineLength(rshape, 0, 0, simultaneous));
_dashMoveTo(dash, offIdx, offset, pts);
cmds++;
pts++;
@ -331,9 +385,12 @@ static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* trans
break;
}
case PathCommand::MoveTo: {
if (rshape->stroke->trim.simultaneous) _dashMoveTo(dash, offIdx, offset, pts);
else _dashMoveTo(dash, pts);
if (trimmed) {
if (simultaneous) {
_trimPattern(&dash, rshape, _outlineLength(rshape, pts - startPts, cmds - startCmds, true));
_dashMoveTo(dash, offIdx, offset, pts);
} else _dashMoveTo(dash, pts);
} else _dashMoveTo(dash, offIdx, offset, pts);
++pts;
break;
}
@ -359,56 +416,6 @@ static SwOutline* _genDashOutline(const RenderShape* rshape, const Matrix* trans
}
static float _outlineLength(const RenderShape* rshape)
{
const PathCommand* cmds = rshape->path.cmds.data;
auto cmdCnt = rshape->path.cmds.count;
const Point* pts = rshape->path.pts.data;
auto ptsCnt = rshape->path.pts.count;
//No actual shape data
if (cmdCnt == 0 || ptsCnt == 0) return 0.0f;
const Point* close = nullptr;
auto length = 0.0f;
auto slength = -1.0f;
auto simultaneous = rshape->stroke->trim.simultaneous;
//Compute the whole length
while (cmdCnt-- > 0) {
switch (*cmds) {
case PathCommand::Close: {
length += mathLength(pts - 1, close);
//retrieve the max length of the shape if the simultaneous mode.
if (simultaneous) {
if (slength < length) slength = length;
length = 0.0f;
}
break;
}
case PathCommand::MoveTo: {
close = pts;
++pts;
break;
}
case PathCommand::LineTo: {
length += mathLength(pts - 1, pts);
++pts;
break;
}
case PathCommand::CubicTo: {
length += bezLength({*(pts - 1), *pts, *(pts + 1), *(pts + 2)});
pts += 3;
break;
}
}
++cmds;
}
if (simultaneous && slength > length) return slength;
else return length;
}
static bool _axisAlignedRect(const SwOutline* outline)
{
//Fast Track: axis-aligned rectangle?
@ -585,11 +592,10 @@ bool shapeGenStrokeRle(SwShape* shape, const RenderShape* rshape, const Matrix*
auto dashStroking = false;
auto ret = true;
auto length = rshape->strokeTrim() ? _outlineLength(rshape) : 0.0f;
//Dash style (+trimming)
if (rshape->stroke->dashCnt > 0 || length > 0) {
shapeOutline = _genDashOutline(rshape, transform, length, mpool, tid);
auto trimmed = rshape->strokeTrim();
if (rshape->stroke->dashCnt > 0 || trimmed) {
shapeOutline = _genDashOutline(rshape, transform, trimmed, mpool, tid);
if (!shapeOutline) return false;
dashStroking = true;
//Normal style