From 4d72eeda1556e179ecf7b60bc2a7829a476ef8e8 Mon Sep 17 00:00:00 2001
From: Hermet Park <chuneon.park@samsung.com>
Date: Tue, 21 Jul 2020 20:24:25 +0900
Subject: [PATCH] sw_engine: revise scale transform logic.

Basically, stroke width size is linear,

engine couldn't apply scale factor from the matrix which contains 2 dimensional values.

Thus, we can apply it if the scale factor of x/y is identical.

Otherwise, we should transform every stroke points in the stroking process.
That scenario can be improved with another patch.

Change-Id: I070dcf29d2e42f21e182bdf4239781464158ef73
---
 src/lib/sw_engine/tvgSwCommon.h     |  5 +++--
 src/lib/sw_engine/tvgSwRenderer.cpp |  4 ++--
 src/lib/sw_engine/tvgSwShape.cpp    |  4 ++--
 src/lib/sw_engine/tvgSwStroke.cpp   | 11 +++++++++--
 src/lib/tvgRender.h                 |  2 +-
 5 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/lib/sw_engine/tvgSwCommon.h b/src/lib/sw_engine/tvgSwCommon.h
index 3639166..b1d38af 100644
--- a/src/lib/sw_engine/tvgSwCommon.h
+++ b/src/lib/sw_engine/tvgSwCommon.h
@@ -156,6 +156,7 @@ struct SwStroke
     bool firstPt;
     bool openSubPath;
     bool handleWideStrokes;
+    bool preScaled;
 };
 
 struct SwDashStroke
@@ -259,7 +260,7 @@ bool shapeGenOutline(SwShape& shape, const Shape* sdata, const Matrix* transform
 bool shapePrepare(SwShape& shape, const Shape* sdata, const SwSize& clip, const Matrix* transform);
 bool shapeGenRle(SwShape& shape, const Shape* sdata, const SwSize& clip, bool antiAlias);
 void shapeDelOutline(SwShape& shape);
-void shapeResetStroke(SwShape& shape, const Shape* sdata);
+void shapeResetStroke(SwShape& shape, const Shape* sdata, const Matrix* transform);
 bool shapeGenStrokeRle(SwShape& shape, const Shape* sdata, const Matrix* transform, const SwSize& clip);
 void shapeFree(SwShape& shape);
 void shapeDelStroke(SwShape& shape);
@@ -267,7 +268,7 @@ bool shapeGenFillColors(SwShape& shape, const Fill* fill, const Matrix* transfor
 void shapeResetFill(SwShape& shape);
 void shapeDelFill(SwShape& shape);
 
-void strokeReset(SwStroke& stroke, const Shape* shape);
+void strokeReset(SwStroke& stroke, const Shape* shape, const Matrix* transform);
 bool strokeParseOutline(SwStroke& stroke, const SwOutline& outline);
 SwOutline* strokeExportOutline(SwStroke& stroke);
 void strokeFree(SwStroke* stroke);
diff --git a/src/lib/sw_engine/tvgSwRenderer.cpp b/src/lib/sw_engine/tvgSwRenderer.cpp
index 7c3ca8d..aac6d8e 100644
--- a/src/lib/sw_engine/tvgSwRenderer.cpp
+++ b/src/lib/sw_engine/tvgSwRenderer.cpp
@@ -211,7 +211,7 @@ void* SwRenderer::prepare(const Shape& sdata, void* data, const RenderTransform*
         //Stroke
         if (task->flags & (RenderUpdateFlag::Stroke | RenderUpdateFlag::Transform)) {
             if (strokeAlpha > 0) {
-                shapeResetStroke(task->shape, task->sdata);
+                shapeResetStroke(task->shape, task->sdata, task->transform);
                 if (!shapeGenStrokeRle(task->shape, task->sdata, task->transform, task->clip)) return;
             } else {
                 shapeDelStroke(task->shape);
@@ -257,4 +257,4 @@ SwRenderer* SwRenderer::inst()
     return static_cast<SwRenderer*>(RenderInitializer::inst(renderInit));
 }
 
-#endif /* _TVG_SW_RENDERER_CPP_ */
+#endif /* _TVG_SW_RENDERER_CPP_ */
\ No newline at end of file
diff --git a/src/lib/sw_engine/tvgSwShape.cpp b/src/lib/sw_engine/tvgSwShape.cpp
index d302fd7..c3aced8 100644
--- a/src/lib/sw_engine/tvgSwShape.cpp
+++ b/src/lib/sw_engine/tvgSwShape.cpp
@@ -618,13 +618,13 @@ void shapeDelStroke(SwShape& shape)
 }
 
 
-void shapeResetStroke(SwShape& shape, const Shape* sdata)
+void shapeResetStroke(SwShape& shape, const Shape* sdata, const Matrix* transform)
 {
     if (!shape.stroke) shape.stroke = static_cast<SwStroke*>(calloc(1, sizeof(SwStroke)));
     auto stroke = shape.stroke;
     assert(stroke);
 
-    strokeReset(*stroke, sdata);
+    strokeReset(*stroke, sdata, transform);
 
     rleFree(shape.strokeRle);
     shape.strokeRle = nullptr;
diff --git a/src/lib/sw_engine/tvgSwStroke.cpp b/src/lib/sw_engine/tvgSwStroke.cpp
index d45ddd8..abaf455 100644
--- a/src/lib/sw_engine/tvgSwStroke.cpp
+++ b/src/lib/sw_engine/tvgSwStroke.cpp
@@ -818,11 +818,18 @@ void strokeFree(SwStroke* stroke)
 }
 
 
-void strokeReset(SwStroke& stroke, const Shape* sdata)
+void strokeReset(SwStroke& stroke, const Shape* sdata, const Matrix* transform)
 {
     assert(sdata);
 
-    stroke.width = TO_SWCOORD(sdata->strokeWidth() * 0.5);
+    //If x/y scale factor is identical, we can scale width size simply.
+    auto scale = 1.0f;
+    if (transform && fabsf(transform->e11 - transform->e22) < FLT_EPSILON) {
+        scale = transform->e11;
+        stroke.preScaled = true;
+    }
+
+    stroke.width = TO_SWCOORD(sdata->strokeWidth() * 0.5 * scale);
     stroke.cap = sdata->strokeCap();
 
     //Save line join: it can be temporarily changed when stroking curves...
diff --git a/src/lib/tvgRender.h b/src/lib/tvgRender.h
index 576961e..6a0897e 100644
--- a/src/lib/tvgRender.h
+++ b/src/lib/tvgRender.h
@@ -32,7 +32,7 @@ enum RenderUpdateFlag {None = 0, Path = 1, Color = 2, Gradient = 4, Stroke = 8,
 
 struct RenderTransform
 {
-    Matrix m;  //3x3 Matrix Elements
+    Matrix m;             //3x3 Matrix Elements
     float x = 0.0f;
     float y = 0.0f;
     float degree = 0.0f;  //rotation degree
-- 
2.7.4