[PATCH v3 0/3] MR4207: gdiplus: Fix GdipAddPathCurve3 curve calculation with offset and nseg variables

[Bartosz Kosiorek (＠gang65)]

The MR is divided to three commits:
 1. Extend AddPathCurve3 test with offset and nseg variables
 2. Moving main curve implementation from GdipAddPathCurve2 to GdipAddPathCurve3, allow for use offset and nseg variables in GdipAddPathCurve3. The offset and nseg variables, will be used for fixing curve calculation in next commit.
 3. Fix GdipAddPathCurve3 curve calculation with offset and nseg variables

--
  v3: gdiplus: Fix GdipAddPathCurve3 curve calculation with offset and nseg variables
      gdiplus: Move main Curve implementation from GdipAddPathCurve2 to GdipAddPathCurve3
      gdiplus/test: Extend AddPathCurve3 test with offset and nseg

https://gitlab.winehq.org/wine/wine/-/merge_requests/4207

[PATCH v3 1/3] gdiplus/test: Extend AddPathCurve3 test with offset and nseg

[Bartosz Kosiorek]

From: Bartosz Kosiorek

---
 dlls/gdiplus/tests/graphicspath.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/dlls/gdiplus/tests/graphicspath.c b/dlls/gdiplus/tests/graphicspath.c
index 238305c3c24..f4099555dae 100644
--- a/dlls/gdiplus/tests/graphicspath.c
+++ b/dlls/gdiplus/tests/graphicspath.c
@@ -954,6 +954,19 @@ static path_test_t addcurve_path3[] = {
     {23.3, 13.3, PathPointTypeBezier, 0, 0}, /*5*/
     {30.0, 10.0, PathPointTypeBezier, 0, 0}  /*6*/
     };
+static path_test_t addcurve_path4[] = {
+    {0.0,  0.0,  PathPointTypeStart,  0, 0}, /*0*/
+    {3.33, 3.33, PathPointTypeBezier, 0, 0}, /*1*/
+    {6.66, 3.33, PathPointTypeBezier, 0, 1}, /*2*/
+    {10.0, 10.0, PathPointTypeBezier, 0, 0}, /*3*/
+    };
+static path_test_t addcurve_path5[] = {
+    {10.0, 10.0, PathPointTypeStart,  0, 0}, /*0*/
+    {13.3, 16.6, PathPointTypeBezier, 0, 1}, /*1*/
+    {3.33, 20.0, PathPointTypeBezier, 0, 1}, /*2*/
+    {10.0, 20.0, PathPointTypeBezier, 0, 0}  /*3*/
+    };
+
 static void test_addcurve(void)
 {
     GpStatus status;
@@ -1027,9 +1040,23 @@ static void test_addcurve(void)
     ok_path(path, addcurve_path, ARRAY_SIZE(addcurve_path), FALSE);
     GdipResetPath(path);

+    /* Skip first point */
     status = GdipAddPathCurve3(path, points, 4, 1, 2, 1.0);
     expect(Ok, status);
     ok_path(path, addcurve_path3, ARRAY_SIZE(addcurve_path3), FALSE);
+    GdipResetPath(path);
+
+    /* Skip two last points */
+    status = GdipAddPathCurve3(path, points, 4, 0, 1, 1.0);
+    expect(Ok, status);
+    ok_path(path, addcurve_path4, ARRAY_SIZE(addcurve_path4), FALSE);
+    GdipResetPath(path);
+
+    /* Skip first and last points */
+    status = GdipAddPathCurve3(path, points, 4, 1, 1, 1.0);
+    expect(Ok, status);
+    ok_path(path, addcurve_path5, ARRAY_SIZE(addcurve_path5), FALSE);
+    GdipResetPath(path);

GdipDeletePath(path);
 }

[PATCH v3 2/3] gdiplus: Move main Curve implementation from GdipAddPathCurve2 to GdipAddPathCurve3

[Bartosz Kosiorek]

From: Bartosz Kosiorek

Moving main curve implementation from GdipAddPathCurve2
to GdipAddPathCurve3, allow for use offset and nseg
variables in GdipAddPathCurve3.
The offset and nseg variables, will be used
for fixing curve calculation in next commit.
---
 dlls/gdiplus/graphicspath.c | 89 ++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 51 deletions(-)

diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c
index 74fdfa6cf45..b65d574e73b 100644
--- a/dlls/gdiplus/graphicspath.c
+++ b/dlls/gdiplus/graphicspath.c
@@ -534,33 +534,26 @@ GpStatus WINGDIPAPI GdipAddPathCurve(GpPath *path, GDIPCONST GpPointF *points, I
 {
     TRACE("(%p, %p, %d)\n", path, points, count);

-    if(!path || !points || count <= 1)
-        return InvalidParameter;
-
-    return GdipAddPathCurve2(path, points, count, 0.5);
+    return GdipAddPathCurve3(path, points, count, 0, count - 1, 0.5);
 }

GpStatus WINGDIPAPI GdipAddPathCurveI(GpPath *path, GDIPCONST GpPoint *points, INT count)
 {
     TRACE("(%p, %p, %d)\n", path, points, count);

-    if(!path || !points || count <= 1)
-        return InvalidParameter;
-
-    return GdipAddPathCurve2I(path, points, count, 0.5);
+    return GdipAddPathCurve3I(path, points, count, 0, count - 1, 0.5);
 }

-GpStatus WINGDIPAPI GdipAddPathCurve2(GpPath *path, GDIPCONST GpPointF *points, INT count,
-    REAL tension)
+GpStatus WINGDIPAPI GdipAddPathCurve3(GpPath *path, GDIPCONST GpPointF *points,
+    INT count, INT offset, INT nseg, REAL tension)
 {
-    INT i, len_pt = count*3-2;
+    INT i, len_pt = nseg * 3 + 1;
     GpPointF *pt;
     REAL x1, x2, y1, y2;
     GpStatus stat;
+    TRACE("(%p, %p, %d, %d, %d, %.2f)\n", path, points, count, offset, nseg, tension);

-    TRACE("(%p, %p, %d, %.2f)\n", path, points, count, tension);
-
-    if(!path || !points || count <= 1)
+    if(!path || !points || offset + 1 >= count || count - offset < nseg + 1 || nseg < 1)
         return InvalidParameter;

pt = heap_alloc_zero(len_pt * sizeof(GpPointF));
@@ -569,32 +562,32 @@ GpStatus WINGDIPAPI GdipAddPathCurve2(GpPath *path, GDIPCONST GpPointF *points,

tension = tension * TENSION_CONST;

-    calc_curve_bezier_endp(points[0].X, points[0].Y, points[1].X, points[1].Y,
+    calc_curve_bezier_endp(points[offset].X, points[offset].Y, points[offset + 1].X, points[offset + 1].Y,
         tension, &x1, &y1);

-    pt[0].X = points[0].X;
-    pt[0].Y = points[0].Y;
+    pt[0].X = points[offset].X;
+    pt[0].Y = points[offset].Y;
     pt[1].X = x1;
     pt[1].Y = y1;

-    for(i = 0; i < count-2; i++){
-        calc_curve_bezier(&(points[i]), tension, &x1, &y1, &x2, &y2);
+    for(i = 0; i < nseg-1; i++){
+        calc_curve_bezier(&(points[offset + i]), tension, &x1, &y1, &x2, &y2);

pt[3*i+2].X = x1;
         pt[3*i+2].Y = y1;
-        pt[3*i+3].X = points[i+1].X;
-        pt[3*i+3].Y = points[i+1].Y;
+        pt[3*i+3].X = points[offset + i + 1].X;
+        pt[3*i+3].Y = points[offset + i + 1].Y;
         pt[3*i+4].X = x2;
         pt[3*i+4].Y = y2;
     }

-    calc_curve_bezier_endp(points[count-1].X, points[count-1].Y,
-        points[count-2].X, points[count-2].Y, tension, &x1, &y1);
+    calc_curve_bezier_endp(points[offset + nseg].X, points[offset + nseg].Y,
+        points[offset + nseg - 1].X, points[offset + nseg - 1].Y, tension, &x1, &y1);

pt[len_pt-2].X = x1;
     pt[len_pt-2].Y = y1;
-    pt[len_pt-1].X = points[count-1].X;
-    pt[len_pt-1].Y = points[count-1].Y;
+    pt[len_pt-1].X = points[offset + nseg].X;
+    pt[len_pt-1].Y = points[offset + nseg].Y;

stat = extend_current_figure(path, pt, len_pt, PathPointTypeBezier);

@@ -605,54 +598,48 @@ GpStatus WINGDIPAPI GdipAddPathCurve2(GpPath *path, GDIPCONST GpPointF *points,

GpStatus WINGDIPAPI GdipAddPathCurve2I(GpPath *path, GDIPCONST GpPoint *points,
     INT count, REAL tension)
+{
+    TRACE("(%p, %p, %d, %.2f)\n", path, points, count, tension);
+
+    return GdipAddPathCurve3I(path, points, count, 0, count - 1, tension);
+}
+
+GpStatus WINGDIPAPI GdipAddPathCurve2(GpPath *path, GDIPCONST GpPointF *points, INT count,
+    REAL tension)
+{
+    TRACE("(%p, %p, %d, %.2f)\n", path, points, count, tension);
+
+    return GdipAddPathCurve3(path, points, count, 0, count - 1, tension);
+}
+
+GpStatus WINGDIPAPI GdipAddPathCurve3I(GpPath *path, GDIPCONST GpPoint *points,
+    INT count, INT offset, INT nseg, REAL tension)
 {
     GpPointF *ptf;
     INT i;
     GpStatus stat;

-    TRACE("(%p, %p, %d, %.2f)\n", path, points, count, tension);
+    TRACE("(%p, %p, %d, %d, %d, %.2f)\n", path, points, count, offset, nseg, tension);

-    if(!path || !points || count <= 1)
+    if(!path || !points || offset + 1 >= count || count - offset < nseg + 1 || nseg < 1)
         return InvalidParameter;

ptf = heap_alloc_zero(sizeof(GpPointF)*count);
     if(!ptf)
         return OutOfMemory;

-    for(i = 0; i < count; i++){
+    for(i = 0; i < count; i++) {
         ptf[i].X = (REAL)points[i].X;
         ptf[i].Y = (REAL)points[i].Y;
     }

-    stat = GdipAddPathCurve2(path, ptf, count, tension);
+    stat = GdipAddPathCurve3(path, ptf, count, offset, nseg, tension);

heap_free(ptf);

return stat;
 }

-GpStatus WINGDIPAPI GdipAddPathCurve3(GpPath *path, GDIPCONST GpPointF *points,
-    INT count, INT offset, INT nseg, REAL tension)
-{
-    TRACE("(%p, %p, %d, %d, %d, %.2f)\n", path, points, count, offset, nseg, tension);
-
-    if(!path || !points || offset + 1 >= count || count - offset < nseg + 1)
-        return InvalidParameter;
-
-    return GdipAddPathCurve2(path, &points[offset], nseg + 1, tension);
-}
-
-GpStatus WINGDIPAPI GdipAddPathCurve3I(GpPath *path, GDIPCONST GpPoint *points,
-    INT count, INT offset, INT nseg, REAL tension)
-{
-    TRACE("(%p, %p, %d, %d, %d, %.2f)\n", path, points, count, offset, nseg, tension);
-
-    if(!path || !points || offset + 1 >= count || count - offset < nseg + 1)
-        return InvalidParameter;
-
-    return GdipAddPathCurve2I(path, &points[offset], nseg + 1, tension);
-}
-
 GpStatus WINGDIPAPI GdipAddPathEllipse(GpPath *path, REAL x, REAL y, REAL width,
     REAL height)
 {

[PATCH v3 3/3] gdiplus: Fix GdipAddPathCurve3 curve calculation with offset and nseg variables

[Bartosz Kosiorek]

From: Bartosz Kosiorek

---
 dlls/gdiplus/graphicspath.c       | 28 ++++++++++++++++++++--------
 dlls/gdiplus/tests/graphicspath.c |  8 ++++----
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c
index b65d574e73b..63f120a6aba 100644
--- a/dlls/gdiplus/graphicspath.c
+++ b/dlls/gdiplus/graphicspath.c
@@ -562,15 +562,23 @@ GpStatus WINGDIPAPI GdipAddPathCurve3(GpPath *path, GDIPCONST GpPointF *points,

tension = tension * TENSION_CONST;

-    calc_curve_bezier_endp(points[offset].X, points[offset].Y, points[offset + 1].X, points[offset + 1].Y,
-        tension, &x1, &y1);
-
     pt[0].X = points[offset].X;
     pt[0].Y = points[offset].Y;
-    pt[1].X = x1;
-    pt[1].Y = y1;
+    if (offset > 0)
+    {
+        calc_curve_bezier(&(points[offset - 1]), tension, &x1, &y1, &x2, &y2);
+        pt[1].X = x2;
+        pt[1].Y = y2;
+    }
+    else
+    {
+        calc_curve_bezier_endp(points[offset].X, points[offset].Y,
+            points[offset + 1].X, points[offset + 1].Y, tension, &x1, &y1);
+        pt[1].X = x1;
+        pt[1].Y = y1;
+    }

-    for(i = 0; i < nseg-1; i++){
+    for (i = 0; i < nseg - 1; i++){
         calc_curve_bezier(&(points[offset + i]), tension, &x1, &y1, &x2, &y2);

pt[3*i+2].X = x1;
@@ -581,8 +589,12 @@ GpStatus WINGDIPAPI GdipAddPathCurve3(GpPath *path, GDIPCONST GpPointF *points,
         pt[3*i+4].Y = y2;
     }

-    calc_curve_bezier_endp(points[offset + nseg].X, points[offset + nseg].Y,
-        points[offset + nseg - 1].X, points[offset + nseg - 1].Y, tension, &x1, &y1);
+    if (offset + nseg + 1 < count)
+        /* If there are one more point in points table then use it for curve calculation */
+        calc_curve_bezier(&(points[offset + nseg - 1]), tension, &x1, &y1, &x2, &y2);
+    else
+        calc_curve_bezier_endp(points[offset + nseg].X, points[offset + nseg].Y,
+            points[offset + nseg - 1].X, points[offset + nseg - 1].Y, tension, &x1, &y1);

pt[len_pt-2].X = x1;
     pt[len_pt-2].Y = y1;
diff --git a/dlls/gdiplus/tests/graphicspath.c b/dlls/gdiplus/tests/graphicspath.c
index f4099555dae..823e1cf38ed 100644
--- a/dlls/gdiplus/tests/graphicspath.c
+++ b/dlls/gdiplus/tests/graphicspath.c
@@ -947,7 +947,7 @@ static path_test_t addcurve_path2[] = {
     };
 static path_test_t addcurve_path3[] = {
     {10.0, 10.0, PathPointTypeStart,  0, 0}, /*0*/
-    {13.3, 16.7, PathPointTypeBezier, 0, 1}, /*1*/
+    {13.3, 16.7, PathPointTypeBezier, 0, 0}, /*1*/
     {3.3,  20.0, PathPointTypeBezier, 0, 0}, /*2*/
     {10.0, 20.0, PathPointTypeBezier, 0, 0}, /*3*/
     {16.7, 20.0, PathPointTypeBezier, 0, 0}, /*4*/
@@ -957,13 +957,13 @@ static path_test_t addcurve_path3[] = {
 static path_test_t addcurve_path4[] = {
     {0.0,  0.0,  PathPointTypeStart,  0, 0}, /*0*/
     {3.33, 3.33, PathPointTypeBezier, 0, 0}, /*1*/
-    {6.66, 3.33, PathPointTypeBezier, 0, 1}, /*2*/
+    {6.66, 3.33, PathPointTypeBezier, 0, 0}, /*2*/
     {10.0, 10.0, PathPointTypeBezier, 0, 0}, /*3*/
     };
 static path_test_t addcurve_path5[] = {
     {10.0, 10.0, PathPointTypeStart,  0, 0}, /*0*/
-    {13.3, 16.6, PathPointTypeBezier, 0, 1}, /*1*/
-    {3.33, 20.0, PathPointTypeBezier, 0, 1}, /*2*/
+    {13.3, 16.6, PathPointTypeBezier, 0, 0}, /*1*/
+    {3.33, 20.0, PathPointTypeBezier, 0, 0}, /*2*/
     {10.0, 20.0, PathPointTypeBezier, 0, 0}  /*3*/
     };