ThorVG

ThorVG classes and enumerations providing C++ APIs. More...

Classes
struct	Point
	A data structure representing a point in two-dimensional space. More...
struct	Matrix
	A data structure representing a three-dimensional matrix. More...
struct	Vertex
	A data structure representing a texture mesh vertex. More...
struct	Polygon
	A data structure representing a triange in a texture mesh. More...
class	Paint
	An abstract class for managing graphical elements. More...
class	Fill
	An abstract class representing the gradient fill of the Shape object. More...
class	Canvas
	An abstract class for drawing graphical elements. More...
class	LinearGradient
	A class representing the linear gradient fill of the Shape object. More...
class	RadialGradient
	A class representing the radial gradient fill of the Shape object. More...
class	Shape
	A class representing two-dimensional figures and their properties. More...
class	Picture
	A class representing an image read in one of the supported formats: raw, svg, png, jpg, lottie(json) and etc. Besides the methods inherited from the Paint, it provides methods to load & draw images on the canvas. More...
class	Scene
	A class to composite children paints. More...
class	Text
	A class to represent text objects in a graphical context, allowing for rendering and manipulation of unicode text. More...
class	SwCanvas
	A class for the rendering graphical elements with a software raster engine. More...
class	GlCanvas
	A class for the rendering graphic elements with a GL raster engine. More...
class	WgCanvas
	A class for the rendering graphic elements with a WebGPU raster engine. More...
class	Initializer
	A class that enables initialization and termination of the TVG engines. More...
class	Animation
	The Animation class enables manipulation of animatable images. More...
class	Saver
	A class for exporting a paint object into a specified file, from which to recover the paint data later. More...
class	Accessor
	The Accessor is a utility class to debug the Scene structure by traversing the scene-tree. More...

Enumerations
enum class	Result {   Success = 0 , InvalidArguments , InsufficientCondition , FailedAllocation ,   MemoryCorruption , NonSupport , Unknown }
	Enumeration specifying the result from the APIs. More...
enum class	PathCommand { Close = 0 , MoveTo , LineTo , CubicTo }
	Enumeration specifying the values of the path commands accepted by TVG. More...
enum class	StrokeCap { Square = 0 , Round , Butt }
	Enumeration determining the ending type of a stroke in the open sub-paths. More...
enum class	StrokeJoin { Bevel = 0 , Round , Miter }
	Enumeration determining the style used at the corners of joined stroked path segments. More...
enum class	FillSpread { Pad = 0 , Reflect , Repeat }
	Enumeration specifying how to fill the area outside the gradient bounds. More...
enum class	FillRule { Winding = 0 , EvenOdd }
	Enumeration specifying the algorithm used to establish which parts of the shape are treated as the inside of the shape. More...
enum class	CompositeMethod {   None = 0 , ClipPath , AlphaMask , InvAlphaMask ,   LumaMask , InvLumaMask , AddMask , SubtractMask ,   IntersectMask , DifferenceMask }
	Enumeration indicating the method used in the composition of two objects - the target and the source. More...
enum class	BlendMethod : uint8_t {   Normal = 0 , Add , Screen , Multiply ,   Overlay , Difference , Exclusion , SrcOver ,   Darken , Lighten , ColorDodge , ColorBurn ,   HardLight , SoftLight }
	Enumeration indicates the method used for blending paint. Please refer to the respective formulas for each method. More...
enum class	CanvasEngine { Sw = (1 << 1) , Gl = (1 << 2) , Wg = (1 << 3) }
	Enumeration specifying the engine type used for the graphics backend. For multiple backends bitwise operation is allowed. More...

Functions
template<typename T = tvg::Paint>
std::unique_ptr< T >	cast (Paint *paint)
	The cast() function is a utility function used to cast a 'Paint' to type 'T'. More...
template<typename T = tvg::Fill>
std::unique_ptr< T >	cast (Fill *fill)
	The cast() function is a utility function used to cast a 'Fill' to type 'T'. More...

Detailed Description

ThorVG classes and enumerations providing C++ APIs.

Enumeration Type Documentation

BlendMethod

enum BlendMethod : uint8_t

strong

Enumeration indicates the method used for blending paint. Please refer to the respective formulas for each method.

Notation: S(source paint as the top layer), D(destination as the bottom layer), Sa(source paint alpha), Da(destination alpha)

See also

Paint::blend()

Note

Experimental API

Enumerator
Normal	Perform the alpha blending(default). S if (Sa == 255), otherwise (Sa * S) + (255 - Sa) * D.
Add	Simply adds pixel values of one layer with the other. (S + D)
Screen	The values of the pixels in the two layers are inverted, multiplied, and then inverted again. (S + D) - (S * D)
Multiply	Takes the RGB channel values from 0 to 255 of each pixel in the top layer and multiples them with the values for the corresponding pixel from the bottom layer. (S * D)
Overlay	Combines Multiply and Screen blend modes. (2 * S * D) if (2 * D < Da), otherwise (Sa * Da) - 2 * (Da - S) * (Sa - D)
Difference	Subtracts the bottom layer from the top layer or the other way around, to always get a non-negative value. (S - D) if (S > D), otherwise (D - S)
Exclusion	The result is twice the product of the top and bottom layers, subtracted from their sum. s + d - (2 * s * d)
SrcOver	Replace the bottom layer with the top layer.
Darken	Creates a pixel that retains the smallest components of the top and bottom layer pixels. min(S, D)
Lighten	Only has the opposite action of Darken Only. max(S, D)
ColorDodge	Divides the bottom layer by the inverted top layer. D / (255 - S)
ColorBurn	Divides the inverted bottom layer by the top layer, and then inverts the result. 255 - (255 - D) / S.
HardLight	The same as Overlay but with the color roles reversed. (2 * S * D) if (S < Sa), otherwise (Sa * Da) - 2 * (Da - S) * (Sa - D)
SoftLight	The same as Overlay but with applying pure black or white does not result in pure black or white. (1 - 2 * S) * (D ^ 2) + (2 * S * D)

CanvasEngine

enum CanvasEngine

strong

Enumeration specifying the engine type used for the graphics backend. For multiple backends bitwise operation is allowed.

Enumerator
Sw	CPU rasterizer.
Gl	OpenGL rasterizer.
Wg	WebGPU rasterizer. (Experimental API)

CompositeMethod

enum CompositeMethod

strong

Enumeration indicating the method used in the composition of two objects - the target and the source.

Notation: S(Source), T(Target), SA(Source Alpha), TA(Target Alpha)

See also

Paint::composite()

Enumerator
None	No composition is applied.
ClipPath	The intersection of the source and the target is determined and only the resulting pixels from the source are rendered.
AlphaMask	Alpha Masking using the compositing target's pixels as an alpha value.
InvAlphaMask	Alpha Masking using the complement to the compositing target's pixels as an alpha value.
LumaMask	Alpha Masking using the grayscale (0.2125R + 0.7154G + 0.0721*B) of the compositing target's pixels. Since 0.9
InvLumaMask	Alpha Masking using the grayscale (0.2125R + 0.7154G + 0.0721*B) of the complement to the compositing target's pixels.
AddMask	Combines the target and source objects pixels using target alpha. (T * TA) + (S * (255 - TA)) (Experimental API)
SubtractMask	Subtracts the source color from the target color while considering their respective target alpha. (T * TA) - (S * (255 - TA)) (Experimental API)
IntersectMask	Computes the result by taking the minimum value between the target alpha and the source alpha and multiplies it with the target color. (T * min(TA, SA)) (Experimental API)
DifferenceMask	Calculates the absolute difference between the target color and the source color multiplied by the complement of the target alpha. abs(T - S * (255 - TA)) (Experimental API)

FillRule

enum FillRule

strong

Enumeration specifying the algorithm used to establish which parts of the shape are treated as the inside of the shape.

Enumerator
Winding	A line from the point to a location outside the shape is drawn. The intersections of the line with the path segment of the shape are counted. Starting from zero, if the path segment of the shape crosses the line clockwise, one is added, otherwise one is subtracted. If the resulting sum is non zero, the point is inside the shape.
EvenOdd	A line from the point to a location outside the shape is drawn and its intersections with the path segments of the shape are counted. If the number of intersections is an odd number, the point is inside the shape.

FillSpread

enum FillSpread

strong

Enumeration specifying how to fill the area outside the gradient bounds.

Enumerator
Pad	The remaining area is filled with the closest stop color.
Reflect	The gradient pattern is reflected outside the gradient area until the expected region is filled.
Repeat	The gradient pattern is repeated continuously beyond the gradient area until the expected region is filled.

PathCommand

enum PathCommand

strong

Enumeration specifying the values of the path commands accepted by TVG.

Not to be confused with the path commands from the svg path element (like M, L, Q, H and many others). TVG interprets all of them and translates to the ones from the PathCommand values.

Enumerator
Close	Ends the current sub-path and connects it with its initial point. This command doesn't expect any points.
MoveTo	Sets a new initial point of the sub-path and a new current point. This command expects 1 point: the starting position.
LineTo	Draws a line from the current point to the given point and sets a new value of the current point. This command expects 1 point: the end-position of the line.
CubicTo	Draws a cubic Bezier curve from the current point to the given point using two given control points and sets a new value of the current point. This command expects 3 points: the 1st control-point, the 2nd control-point, the end-point of the curve.

Result

enum Result

strong

Enumeration specifying the result from the APIs.

Enumerator
Success	The value returned in case of a correct request execution.
InvalidArguments	The value returned in the event of a problem with the arguments given to the API - e.g. empty paths or null pointers.
InsufficientCondition	The value returned in case the request cannot be processed - e.g. asking for properties of an object, which does not exist.
FailedAllocation	The value returned in case of unsuccessful memory allocation.
MemoryCorruption	The value returned in the event of bad memory handling - e.g. failing in pointer releasing or casting.
NonSupport	The value returned in case of choosing unsupported options.
Unknown	The value returned in all other cases.

StrokeCap

enum StrokeCap

strong

Enumeration determining the ending type of a stroke in the open sub-paths.

Enumerator
Square	The stroke is extended in both end-points of a sub-path by a rectangle, with the width equal to the stroke width and the length equal to the half of the stroke width. For zero length sub-paths the square is rendered with the size of the stroke width.
Round	The stroke is extended in both end-points of a sub-path by a half circle, with a radius equal to the half of a stroke width. For zero length sub-paths a full circle is rendered.
Butt	The stroke ends exactly at each of the two end-points of a sub-path. For zero length sub-paths no stroke is rendered.

StrokeJoin

enum StrokeJoin

strong

Enumeration determining the style used at the corners of joined stroked path segments.

Enumerator
Bevel	The outer corner of the joined path segments is bevelled at the join point. The triangular region of the corner is enclosed by a straight line between the outer corners of each stroke.
Round	The outer corner of the joined path segments is rounded. The circular region is centered at the join point.
Miter	The outer corner of the joined path segments is spiked. The spike is created by extension beyond the join point of the outer edges of the stroke until they intersect. In case the extension goes beyond the limit, the join style is converted to the Bevel style.

Function Documentation

cast() [1/2]

std::unique_ptr<T> tvg::cast

(

Fill *

fill

)

The cast() function is a utility function used to cast a 'Fill' to type 'T'.

Since

0.11

cast() [2/2]

std::unique_ptr<T> tvg::cast

(

Paint *

paint

)

The cast() function is a utility function used to cast a 'Paint' to type 'T'.

Since

0.11