Window: createImageBitmap() method
The createImageBitmap()
method of the Window
interface creates a bitmap from a given source, optionally cropped to contain only a portion of that source.
It accepts a variety of different image sources, and returns a Promise
which resolves to an ImageBitmap
.
Syntax
createImageBitmap(image)
createImageBitmap(image, options)
createImageBitmap(image, sx, sy, sw, sh)
createImageBitmap(image, sx, sy, sw, sh, options)
Parameters
image
-
An image source, which can be any one of the following:
sx
-
The x coordinate of the reference point of the rectangle from which the
ImageBitmap
will be extracted. sy
-
The y coordinate of the reference point of the rectangle from which the
ImageBitmap
will be extracted. sw
-
The width of the rectangle from which the
ImageBitmap
will be extracted. This value can be negative. sh
-
The height of the rectangle from which the
ImageBitmap
will be extracted. This value can be negative. options
Optional-
An object that sets options for the image's extraction. The available options are:
imageOrientation
-
Specifies how the bitmap image should be oriented.
from-image
-
Image oriented according to EXIF orientation metadata, if present (default).
flipY
-
Image oriented according to EXIF orientation metadata, if present, and then flipped vertically.
none
-
Image oriented according to image encoding, ignoring any metadata about the orientation (such as EXIF metadata, that might be added to an image to indicate that the camera was turned sideways to capture the image in portrait mode).
premultiplyAlpha
-
Specifies whether the bitmap's color channels should be premultiplied by the alpha channel. One of
none
,premultiply
, ordefault
(default). colorSpaceConversion
-
Specifies whether the image should be decoded using color space conversion. Either
none
ordefault
(default). The valuedefault
indicates that implementation-specific behavior is used. resizeWidth
-
A long integer that indicates the output width.
resizeHeight
-
A long integer that indicates the output height.
resizeQuality
-
Specifies the algorithm to be used for resizing the input to match the output dimensions. One of
pixelated
,low
(default),medium
, orhigh
.
Return value
A Promise
which resolves to an ImageBitmap
object containing bitmap data from the given rectangle.
Examples
Creating sprites from a sprite sheet
This example loads a sprite sheet, extracts individual sprites, and then renders each sprite to the canvas. A sprite sheet is an image containing multiple smaller images, each of which you want to be able to render separately.
const canvas = document.getElementById("myCanvas"),
ctx = canvas.getContext("2d"),
image = new Image();
// Wait for the sprite sheet to load
image.onload = () => {
Promise.all([
// Cut out two sprites from the sprite sheet
createImageBitmap(image, 0, 0, 32, 32),
createImageBitmap(image, 32, 0, 32, 32),
createImageBitmap(image, 0, 0, 50, 50, { imageOrientation: "flipY" }),
]).then((sprites) => {
// Draw each sprite onto the canvas
ctx.drawImage(sprites[0], 0, 0);
ctx.drawImage(sprites[1], 32, 32);
ctx.drawImage(sprites[2], 64, 64);
});
};
// Load the sprite sheet from an image file
image.src = "50x50.jpg";
Specifications
Specification |
---|
HTML Standard # dom-createimagebitmap-dev |
Browser compatibility
BCD tables only load in the browser