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[[ CanvasPathArcTo ]] Add tangent lines version of path "arc to ..." command.
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‎engine/src/canvas.mlc‎

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@@ -2675,6 +2675,7 @@ public foreign handler MCCanvasPathLineTo(in pPoint as Point, inout xPath as Pat
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public foreign handler MCCanvasPathCurveThroughPoint(in pThrough as Point, in pTo as Point, inout xPath as Path) returns nothing binds to "<builtin>"
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public foreign handler MCCanvasPathCurveThroughPoints(in pThroughA as Point, in pThroughB as Point, in pTo as Point, inout xPath as Path) returns nothing binds to "<builtin>"
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public foreign handler MCCanvasPathArcTo(in pThrough as Point, in pTo as Point, in pRadius as CanvasFloat, inout xPath as Path) returns nothing binds to "<builtin>"
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public foreign handler MCCanvasPathEllipticArcToWithRadiiAsList(in pTo as Point, in pRadii as List, in pRotation as CanvasFloat, inout xPath as Path) returns nothing binds to "<builtin>"
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public foreign handler MCCanvasPathEllipticArcToWithFlagsWithRadiiAsList(in pTo as Point, in pRadii as List, in pRotation as CanvasFloat, in pLargest as bool, in pClockwise as bool, inout xPath as Path) returns nothing binds to "<builtin>"
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@@ -2753,6 +2754,42 @@ begin
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end syntax
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/*
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Summary: Adds an arc to a path.
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mThrough: An expression which evaluates to a point.
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mTo: An expression which evaluates to a point.
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mRadius: An expression which evaluates to a number.
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mPath: An expression which evaluates to a path.
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Description: Adds an arc between the points of a circle with radius <mRadius> tangent to the lines from the current point to <mThrough>, and from <mThrough> to <mTo>.
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Example:
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// Construct a path tracing out a rectangle with rounded bottom corners.
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variable tPath
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put the empty path into tPath
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// Begin a new subpath
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move to point [0, 0] on tPath
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// Continue path with an arc to the bottom edge
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arc through point [0, my height] to point [25, my height] with radius 25 on tPath
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// Continue path with an arc to the right edge
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arc through point [my width, my height] to point [my width, 0] with radius 25 on tPath
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// Close the path with a line back to the starting point
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close path on tPath
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Tags: Canvas
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*/
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syntax PathOperationArcTo is statement
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"arc" "through" <mThrough: Expression> "to" <mTo: Expression> "with" "radius" <mRadius: Expression> "on" <mPath: Expression>
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begin
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MCCanvasPathArcTo(mThrough, mTo, mRadius, mPath)
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end syntax
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/*
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Summary: Adds an arc to a path.
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‎engine/src/module-canvas.cpp‎

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@@ -3690,6 +3690,32 @@ void MCCanvasPathClosePath(MCCanvasPathRef &x_path)
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MCGPathRelease(t_path);
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}
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void MCCanvasPathArcTo(MCCanvasPointRef p_tangent, MCCanvasPointRef p_to, MCCanvasFloat p_radius, MCCanvasPathRef &x_path)
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{
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bool t_success;
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t_success = true;
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MCGPathRef t_path;
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t_path = nil;
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if (t_success)
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{
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MCGPathMutableCopy(*MCCanvasPathGet(x_path), t_path);
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t_success = MCGPathIsValid(t_path);
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}
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if (t_success)
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{
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MCGPathArcToTangent(t_path, *MCCanvasPointGet(p_tangent), *MCCanvasPointGet(p_to), p_radius);
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t_success = MCGPathIsValid(t_path);
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}
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if (t_success)
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MCCanvasPathSetMCGPath(t_path, x_path);
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MCGPathRelease(t_path);
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}
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void MCCanvasPathEllipticArcToWithFlagsWithRadiiAsList(MCCanvasPointRef p_to, MCProperListRef p_radii, MCCanvasFloat p_rotation, bool p_largest, bool p_clockwise, MCCanvasPathRef &x_path)
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{
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bool t_success;

‎engine/src/module-canvas.h‎

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Original file line numberDiff line numberDiff line change
@@ -441,6 +441,7 @@ extern "C" MC_DLLEXPORT void MCCanvasPathCurveThroughPoint(MCCanvasPointRef p_th
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extern "C" MC_DLLEXPORT void MCCanvasPathCurveThroughPoints(MCCanvasPointRef p_through_a, MCCanvasPointRef p_through_b, MCCanvasPointRef p_to, MCCanvasPathRef &x_path);
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extern "C" MC_DLLEXPORT void MCCanvasPathClosePath(MCCanvasPathRef &x_path);
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extern "C" MC_DLLEXPORT void MCCanvasPathArcTo(MCCanvasPointRef p_tangent, MCCanvasPointRef p_to, MCCanvasFloat p_radius, MCCanvasPathRef &x_path);
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extern "C" MC_DLLEXPORT void MCCanvasPathEllipticArcToWithFlagsWithRadiiAsList(MCCanvasPointRef p_to, MCProperListRef p_radii, MCCanvasFloat p_rotation, bool p_largest, bool p_clockwise, MCCanvasPathRef &x_path);
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extern "C" MC_DLLEXPORT void MCCanvasPathEllipticArcToWithRadiiAsList(MCCanvasPointRef p_to, MCProperListRef p_radii, MCCanvasFloat p_rotation, MCCanvasPathRef &x_path);
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‎libgraphics/include/graphics.h‎

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Original file line numberDiff line numberDiff line change
@@ -783,6 +783,7 @@ void MCGPathQuadraticTo(MCGPathRef path, MCGPoint control_point, MCGPoint end_po
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void MCGPathCubicTo(MCGPathRef path, MCGPoint first_control_point, MCGPoint second_control_point, MCGPoint end_point);
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void MCGPathArcTo(MCGPathRef path, MCGSize radii, MCGFloat rotation, bool large_arc, bool sweep, MCGPoint end_point);
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void MCGPathArcToBestFit(MCGPathRef path, MCGSize p_radii, MCGFloat p_rotation, MCGPoint p_end_point);
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void MCGPathArcToTangent(MCGPathRef path, const MCGPoint &p_tangent, const MCGPoint &p_end, MCGFloat p_radius);
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void MCGPathCloseSubpath(MCGPathRef path);
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void MCGPathThicken(MCGPathRef path, const MCGStrokeAttr& attr, MCGPathRef& r_thick_path);

‎libgraphics/src/path.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -757,6 +757,21 @@ static inline MCGPoint MCGVectorMake(const MCGPoint p_start, MCGPoint p_end)
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return MCGPointMake(p_end.x - p_start.x, p_end.y - p_start.y);
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}
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static inline MCGPoint MCGVectorNormalize(const MCGPoint p_vector)
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{
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return MCGPointScale(p_vector, 1 / MCGVectorMagnitude(p_vector));
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}
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static inline MCGPoint MCGVectorAdd(const MCGPoint &p_left, const MCGPoint &p_right)
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{
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return MCGPointMake(p_left.x + p_right.x, p_left.y + p_right.y);
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}
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static inline MCGPoint MCGVectorScale(const MCGPoint &p_vector, MCGFloat p_scale)
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{
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return MCGPointMake(p_vector.x * p_scale, p_vector.y * p_scale);
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}
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static inline MCGPoint MCGVectorRotate90(const MCGPoint &p_vector)
761776
{
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return MCGPointMake(-p_vector.y, p_vector.x);
@@ -1004,6 +1019,52 @@ void MCGPathArcToBestFit(MCGPathRef self, MCGSize p_radii, MCGFloat p_rotation,
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self -> is_valid = t_success;
10051020
}
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1022+
void MCGPathArcToTangent(MCGPathRef self, const MCGPoint &p_tangent, const MCGPoint &p_end, MCGFloat p_radius)
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{
1024+
if (!MCGPathIsValid(self))
1025+
return;
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bool t_success;
1028+
t_success = true;
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if (t_success)
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t_success = self -> is_mutable;
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if (t_success)
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{
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MCGPoint t_start;
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if (!MCGPathGetCurrentPoint(self, t_start))
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t_start = MCGPointMake(0, 0);
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t_success = !MCGPointIsEqual(t_start, p_tangent) && !MCGPointIsEqual(p_tangent, p_end) && !MCGPointIsEqual(p_end, t_start);
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MCGPoint t_vec1, t_vec2;
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t_vec1 = MCGVectorMake(p_tangent, t_start);
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t_vec2 = MCGVectorMake(p_tangent, p_end);
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MCGFloat t_angle;
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t_angle = MCGAngleBetweenVectors(t_vec1, t_vec2);
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MCGFloat t_dist;
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t_dist = MCAbs(p_radius / tanf(t_angle / 2));
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MCGPoint t_start_tangent, t_end_tangent;
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if (MCGVectorMagnitude(t_vec1) > t_dist)
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t_start_tangent = MCGVectorAdd(p_tangent, MCGVectorScale(MCGVectorNormalize(t_vec1), t_dist));
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else
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t_start_tangent = t_start;
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if (MCGVectorMagnitude(t_vec2) > t_dist)
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t_end_tangent = MCGVectorAdd(p_tangent, MCGVectorScale(MCGVectorNormalize(t_vec2), t_dist));
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else
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t_end_tangent = p_end;
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MCGPathLineTo(self, t_start_tangent);
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MCGPathArcTo(self, MCGSizeMake(p_radius, p_radius), 0, false, t_angle < 0, t_end_tangent);
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MCGPathLineTo(self, p_end);
1065+
}
1066+
}
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void MCGPathCloseSubpath(MCGPathRef self)
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{
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if (!MCGPathIsValid(self))

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