Texture Interface Reference

import"evg.idl";

Collaboration diagram for Texture:

Public Member Functions
	Texture (unsigned long width, unsigned long height, DOMString pixfmt, ArrayBuffer data, optional unsigned long stride=0, optional unsigned long stride_uv=0)
	Texture (DOMString filename, optional boolean is_rel_script=false)
	Texture (ArrayBuffer img_data)
	Texture (unsigned long width, unsigned long height, DOMString pixfmt, Function param_fun, optional boolean use_screen_coords=false)
	Texture (Canvas canvas)
	Texture (FilterPacket packet)
	Texture ()
void	set_alpha (unsigned long alpha)
void	set_alphaf (double alpha)
Texture	rgb2hsv ()
Texture	hsv2rgb ()
Texture	rgb2yuv (Canvas surf)
Texture	yuv2rgb (Canvas surf)
Texture	convolution (ConvolutionKernel k)
Texture	split (unsigned long idx)
void	update (FilterPacket packet)
	load (DOMString filename, optional boolean is_rel_script=false)
	load (ArrayBuffer img_data)
	set_named (DOMString name)
	set_pad_color (DOMString color)
DOMString	get_pad_color ()
Object	get_pixelf (Float s, Float t, optional bool as_array=false)
Object	get_pixel (unsigned long x, unsigned long y, optional bool as_array=false)
Array	diff_score (Texture diff_with, optional DOMString mode="mae", optional boolean split_planes=false)

Data Fields
writeonly unsigned long	filtering
writeonly ColorMatrix	cmx
attribute Matrix2D	mx
attribute boolean	repeat_s
attribute boolean	repeat_t
attribute boolean	flip
readonly attribute boolean	width
readonly attribute boolean	height
readonly attribute DOMString	pixfmt
readonly attribute unsigned long	comp
readonly attribute ArrayBuffet	data

Detailed Description

texture stencil

Constructor & Destructor Documentation

Texture() [1/7]

Texture::Texture	(	unsigned long	width,
		unsigned long	height,
		DOMString	pixfmt,
		ArrayBuffer	data,
		optional unsigned long	stride = 0,
		optional unsigned long	stride_uv = 0
	)

pixel data constructor.

Parameters

width	width of the texture
height	height of the texture
pixfmt	pixel format of the texture
data	texture data to use
stride	stride of pixel buffer or of first plane for planar formats
stride_uv	stride of second plane for planar formats

Texture() [2/7]

Texture::Texture	(	DOMString	filename,
		optional boolean	is_rel_script = false
	)

image file constructor. Only JPEG and PNG local files are supported. This constructor is used to quickly load an image file without using a filter chain for that

Parameters

filename	file name on local drive
is_rel_script	if true, indicates the file path is relative to the script location. Otherwise it is relative to the current directory

Texture() [3/7]

Texture::Texture

(

ArrayBuffer

img_data

)

ArrayBuffer. Only JPEG and PNG local files are supported. This constructor is used to quickly load an image file without using a filter chain for that

Parameters

img_data

array buffer containing the compressed image data

Texture() [4/7]

Texture::Texture	(	unsigned long	width,
		unsigned long	height,
		DOMString	pixfmt,
		Function	param_fun,
		optional boolean	use_screen_coords = false
	)

parametric texture constructor. A parametric texture gets its pixel values from a javascript callback function, the resulting value being blended according to the antialiasing level of the pixel. This allows creating rather complex custom textures, in a fashion similar to fragment shaders.

Warning

Parametric textures in JS cannot use multithreaded canvas, use 2D shaders for that.

Parameters

width	width of the texture
height	height of the texture
pixfmt	pixel format of the texture
param_fun	texture data to use. This function is called on the texture object with two parameters x and y indicating the desired pixel in the texture, where (0,0) is top-left; the function shall return a Colorf interface
use_screen_coords	if set, the calbback function is passed screen coordinates rather than texture coordinates (and width/height of texture are ignored)

Texture() [5/7]

Texture::Texture

(

Canvas

canvas

)

canvas constructor.

Note

There is no restriction on the source canvas, you can even use the target drawing canvas as a source to produce nice effects.

Parameters

canvas

the canvas to use as a texture

Texture() [6/7]

Texture::Texture

(

FilterPacket

packet

)

packet constructor. This is usually needed for planar YUV format where planes are not contiguous in memory (eg output of hardware decoder). The size of the pixel buffer will be derived from the packet's PID properties

Parameters

packet

the source packet to use as a source for the data

Texture() [7/7]

Texture::Texture

(

)

Empty texture constructor. This is usually needed async texture load.

Member Function Documentation

set_alpha()

void Texture::set_alpha

(

unsigned long

alpha

)

sets alpha value for stencil. The alpha is multiplied with the alpha component of the solid brush or gradient color

Parameters

alpha

the alpha to set, between 0 and 255

set_alphaf()

void Texture::set_alphaf

(

double

alpha

)

sets alpha value for stencil. The alpha is multiplied with the alpha component of the solid brush or gradient color

Parameters

alpha

the alpha to set, between 0.0 and 1.0

rgb2hsv()

Texture Texture::rgb2hsv

(

)

converts texture from RGB/YUV to new HSV texture

Warning

the texture format will still be RGB (or RGBA if the source has alpha), in packed format

experimental, slow

Returns

new texture

hsv2rgb()

Texture Texture::hsv2rgb

(

)

converts texture from HSV to new RGB texture

Warning

experimental, slow

Returns

new texture

rgb2yuv()

Texture Texture::rgb2yuv

(

Canvas

surf

)

converts texture from RGB to new YUV texture

Warning

experimental, slow This function can be used to convert an RGB texture to a YUV one, typically for rasterizing an RGB static texture over a YUV video (avoids performing the RGB to YUV conversion at each frame)

Parameters

surf	the target Canvas

Returns

new texture

yuv2rgb()

Texture Texture::yuv2rgb

(

Canvas

surf

)

converts texture from YUV to new RGB texture

Warning

experimental, slow This function can be used to convert a YUV texture to an RGB one, typically for rasterizing a YUV static texture over an RGB video (avoids performing the TYV to RGB conversion at each frame)

Parameters

surf	the target Canvas

Returns

new texture

convolution()

Texture Texture::convolution

(

ConvolutionKernel

k

)

performs a convolution on the texture

Warning

experimental, slow

Parameters

k	the convolution kernel to use

Returns

new texture

split()

Texture Texture::split

(

unsigned long

idx

)

splits the given component into a new texture

Warning

experimental, slow (uses pixel by pixel access)

Parameters

idx	the component index. 0 is red or greyscale, 1 is alpha (alhpagrey formats) or green, 2 is green and 4 is alpha

Returns

new texture

update()

void Texture::update

(

FilterPacket

packet

)

updates pixel data of texture using source packet

Parameters

packet

the new packet to use for the texture

load() [1/2]

Texture::load	(	DOMString	filename,
		optional boolean	is_rel_script = false
	)

load local file into texture. Only JPEG and PNG local files are supported.

Parameters

filename	file name on local drive
is_rel_script	if true, indicates the file path is relative to the script location. Otherwise it is relative to the current directory

load() [2/2]

Texture::load

(

ArrayBuffer

img_data

)

load file data into texture. Only JPEG and PNG data are supported.

Parameters

img_data

image file data

set_named()

Texture::set_named

(

DOMString

name

)

Makes the texture a named texture for WebGL.

If a texImage2D is done with a named EVG texture:

• the associated WebGL texture becomes a named texture
• any update() on the EVG texture will update the WebGL texture.

Warning

The shaders must be (re)compiled after the first update() on the texture.

Parameters

name	the named texture to use.

set_pad_color()

Texture::set_pad_color

(

DOMString

color

)

Sets padding color for texture - see gf_evg_stencil_set_pad_color

The parameters can also be 4 doubles, an array of 4 doubles or an object with 'r', 'g', 'b', 'a' properties. In these cases, the component values must be between 0 and 1

Parameters

color

the color to use.

get_pad_color()

DOMString Texture::get_pad_color

(

)

gets padding color associated for texture

Returns

the color used to pad or null if none.

get_pixelf()

Object Texture::get_pixelf	(	Float	s,
		Float	t,
		optional bool	as_array = false
	)

gets RGB pixel value in a texture

Parameters

s	horizontal normalized texture coordinate of pixel, between 0 (left) and 1.0 (right)
t	vertical normalized texture coordinate of pixel, between 0 (top) and 1.0 (bottom)
as_array	if true, the return object is an array of 4 components, otherwise it is a Color object

Returns

the converted value

get_pixel()

Object Texture::get_pixel	(	unsigned long	x,
		unsigned long	y,
		optional bool	as_array = false
	)

gets RGB pixel value in a texture

Parameters

x	horizontal coordinate of pixel, between 0 (left) and width (right)
y	vertical coordinate of pixel, between 0 (top) and height (bottom)
as_array	if true, the return object is an array of 4 components, otherwise it is a Color object

Returns

the converted value

diff_score()

Array Texture::diff_score	(	Texture	diff_with,
		optional DOMString	mode = "mae",
		optional boolean	split_planes = false
	)

gets MAE (Mean Absolute Error) and/or MSE (Mean Square Error) metric of texture compared with another texture. Both textures shall have the same size and pixel format.

Parameters

diff_with	texture to compute difference with
mode	string indicating metric(s) to compute as a comma-separated list. Currently only 'mae' and 'mse' are supported.
split_planes	if true, metrics are computed per plane, otherwise averaged on all planes. For YUV textures, if this is not set, metric is only computed on luma plane and alpha plane if present.

Returns

an array of object, each containing 'mae' and 'mse' properties. Values are numbers between 0 (all identical) and 100 (all pixels have full intensity difference).

If split_planes is false, the array contains a single object. Otherwise, it contains 4 objects if alpha plane or 3 otherwise, in {R,G,B,A} or {Y,U,V,A} order.

Field Documentation

filtering

writeonly unsigned long Texture::filtering

filtering mode - see gf_evg_stencil_set_filter

cmx

writeonly ColorMatrix Texture::cmx

color matrix - see gf_evg_stencil_set_color_matrix. Setting to null resets the color matrix

mx

attribute Matrix2D Texture::mx

matrix - see gf_evg_stencil_set_matrix. Setting to null resets the matrix

Warning

: this is a copy of the associated matrix, not a live object

repeat_s

attribute boolean Texture::repeat_s

horizontal repeat flag

repeat_t

attribute boolean Texture::repeat_t

vertical repeat flag

flip

attribute boolean Texture::flip

vertical flip flag

width

readonly attribute boolean Texture::width

width in pixels of image (RGB width or luma plane width)

height

readonly attribute boolean Texture::height

height in pixels of image (RGB height or luma plane height)

pixfmt

readonly attribute DOMString Texture::pixfmt

pixel format

comp

readonly attribute unsigned long Texture::comp

number of components

data

readonly attribute ArrayBuffet Texture::data

texture data