Web/API/WebGLRenderingContext/pixelStorei

The WebGLRenderingContext.pixelStorei() method of the WebGL API specifies the pixel storage modes.

Syntax

void gl.pixelStorei(pname, param);

Parameters

pname: A Glenum specifying which parameter to set. See below for possible values.
param: A GLint specifying a value to set the pname parameter to. See below for possible values.

Return value

None.

Pixel storage parameters

Parameter name (for `pname`)	Description	Type	Default value	Allowed values (for `param`)	Specified in
`gl.PACK_ALIGNMENT`	Packing of pixel data into memory	`GLint`	4	1, 2, 4, 8	OpenGL ES 2.0
`gl.UNPACK_ALIGNMENT`	Unpacking of pixel data from memory.	`GLint`	4	1, 2, 4, 8	OpenGL ES 2.0
`gl.UNPACK_FLIP_Y_WEBGL`	Flips the source data along its vertical axis if true.	`GLboolean`	false	true, false	WebGL
`gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL`	Multiplies the alpha channel into the other color channels	`GLboolean`	false	true, false	WebGL
`gl.UNPACK_COLORSPACE_CONVERSION_WEBGL`	Default color space conversion or no color space conversion.	`GLenum`	`gl.BROWSER_DEFAULT_WEBGL`	`gl.BROWSER_DEFAULT_WEBGL`, `gl.NONE`	WebGL

When using a WebGL 2 context, the following values are available additionally:

Constant	Description	Type	Allowed values (for `param`)	Specified in
`gl.PACK_ROW_LENGTH`	Number of pixels in a row.	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.PACK_SKIP_PIXELS`	Number of pixel locations skipped before the first pixel is written into memory.	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.PACK_SKIP_ROWS`	Number of rows of pixel locations skipped before the first pixel is written into memory	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_ROW_LENGTH`	Number of pixels in a row.	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_IMAGE_HEIGHT`	Image height used for reading pixel data from memory	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_SKIP_PIXELS`	Number of pixel images skipped before the first pixel is read from memory	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_SKIP_ROWS`	Number of rows of pixel locations skipped before the first pixel is read from memory	`GLint`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_SKIP_IMAGES`	Number of pixel images skipped before the first pixel is read from memory	`GLint`	0 to `Infinity`	OpenGL ES 3.0

Examples

Setting the pixel storage mode affects the WebGLRenderingContext.readPixels() operations, as well as unpacking of textures with the WebGLRenderingContext.texImage2D() and WebGLRenderingContext.texSubImage2D() methods.

var tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.PACK_ALIGNMENT, 4);

To check the values for packing and unpacking of pixel data, you can query the same pixel storage parameters with WebGLRenderingContext.getParameter().

gl.getParameter(gl.PACK_ALIGNMENT);
gl.getParameter(gl.UNPACK_ALIGNMENT);

Specifications

Specification	Status	Comment
WebGL 1.0The definition of 'pixelStorei' in that specification.	Recommendation	Initial definition for WebGL.
WebGL 1.0The definition of 'Pixel Storage Parameters' in that specification.	Recommendation	Additional pixel storage parameters that aren't specified in OpenGL.
OpenGL ES 2.0The definition of 'glPixelStorei' in that specification.	Standard	Man page of the OpenGL ES 2.0 API.
WebGL 2.0The definition of 'pixelStorei' in that specification.	Editor's Draft	Updated definition for WebGL 2.
OpenGL ES 3.0The definition of 'glPixelStorei' in that specification.	Standard	Man page of the OpenGL ES 3.0 API.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`pixelStorei`	Chrome Full support 9	Edge Full support 12	Firefox Full support 4	IE Full support 11	Opera Full support 12	Safari Full support 5.1	WebView Android Full support Yes	Chrome Android Full support 25	Firefox Android Full support Yes	Opera Android Full support 12	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
`WebGL2`	Chrome Full support 56	Edge Full support 79	Firefox Full support 51	IE No support No	Opera Full support 43	Safari No support No	WebView Android Full support 58	Chrome Android Full support 58	Firefox Android Full support 51	Opera Android Full support 43	Safari iOS No support No	Samsung Internet Android Full support 7.0

Legend

Full support: Full support
No support: No support