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gecko-dev/dom/webidl/ImageBitmap.webidl

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/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/.
*
* The origin of this IDL file is
* https://html.spec.whatwg.org/multipage/webappapis.html#images
*
* The origin of the extended IDL file is
* http://w3c.github.io/mediacapture-worker/#imagebitmap-extensions
*/
typedef (CanvasImageSource or
Blob or
CanvasRenderingContext2D or // This is out of spec.
ImageData) ImageBitmapSource;
[Exposed=(Window,Worker)]
interface ImageBitmap {
[Constant]
readonly attribute unsigned long width;
[Constant]
readonly attribute unsigned long height;
};
// It's crucial that there be a way to explicitly dispose of ImageBitmaps
// since they refer to potentially large graphics resources. Some uses
// of this API proposal will result in repeated allocations of ImageBitmaps,
// and garbage collection will not reliably reclaim them quickly enough.
// Here we reuse close(), which also exists on another Transferable type,
// MessagePort. Potentially, all Transferable types should inherit from a
// new interface type "Closeable".
partial interface ImageBitmap {
// Dispose of all graphical resources associated with this ImageBitmap.
void close();
};
// ImageBitmap-extensions
// Bug 1141979 - [FoxEye] Extend ImageBitmap with interfaces to access its
// underlying image data
/*
* An image or a video frame is conceptually a two-dimensional array of data and
* each element in the array is called a pixel. The pixels are usually stored in
* a one-dimensional array and could be arranged in a variety of image formats.
* Developers need to know how the pixels are formatted so that they are able to
* process them.
*
* The image format describes how pixels in an image are arranged. A single
* pixel has at least one, but usually multiple pixel values. The range of a
* pixel value varies, which means different image formats use different data
* types to store a single pixel value.
*
* The most frequently used data type is 8-bit unsigned integer whose range is
* from 0 to 255, others could be 16-bit integer or 32-bit floating points and
* so forth. The number of pixel values of a single pixel is called the number
* of channels of the image format. Multiple pixel values of a pixel are used
* together to describe the captured property which could be color or depth
* information. For example, if the data is a color image in RGB color space,
* then it is a three-channel image format and a pixel is described by R, G and
* B three pixel values with range from 0 to 255. As another example, if the
* data is a gray image, then it is a single-channel image format with 8-bit
* unsigned integer data type and the pixel value describes the gray scale. For
* depth data, it is a single channel image format too, but the data type is
* 16-bit unsigned integer and the pixel value is the depth level.
*
* For those image formats whose pixels contain multiple pixel values, the pixel
* values might be arranged in one of the following ways:
* 1) Planar pixel layout:
* each channel has its pixel values stored consecutively in separated
* buffers (a.k.a. planes) and then all channel buffers are stored
* consecutively in memory.
* (Ex: RRRRRR......GGGGGG......BBBBBB......)
* 2) Interleaving pixel layout:
* each pixel has its pixel values from all channels stored together and
* interleaves all channels.
* (Ex: RGBRGBRGBRGBRGB......)
*/
/*
* The ImageBitmap extensions use this enumeration to negotiate the image format
* while 1) accessing the underlying data of an ImageBitmap and
* 2) creating a new ImageBitmap.
*
* For each format in this enumeration, we use a 2x2 small image (4 pixels) as
* example to illustrate the pixel layout.
*
* 2x2 image: +--------+--------+
* | pixel1 | pixel2 |
* +--------+--------+
* | pixel3 | pixel4 |
* +--------+--------+
*
*/
enum ImageBitmapFormat {
/*
* Channel order: R, G, B, A
* Channel size: full rgba-chennels
* Pixel layout: interleaving rgba-channels
* Pixel layout illustration:
* [Plane1]: R1 G1 B1 A1 R2 G2 B2 A2 R3 G3 B3 A3 R4 G4 B4 A4
* Data type: 8-bit unsigned integer
*/
"RGBA32",
/*
* Channel order: B, G, R, A
* Channel size: full bgra-channels
* Pixel layout: interleaving bgra-channels
* Pixel layout illustration:
* [Plane1]: B1 G1 R1 A1 B2 G2 R2 A2 B3 G3 R3 A3 B4 G4 R4 A4
* Data type: 8-bit unsigned integer
*/
"BGRA32",
/*
* Channel order: R, G, B
* Channel size: full rgb-channels
* Pixel layout: interleaving rgb-channels
* Pixel layout illustration:
* [Plane1]: R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4
* Data type: 8-bit unsigned integer
*/
"RGB24",
/*
* Channel order: B, G, R
* Channel size: full bgr-channels
* Pixel layout: interleaving bgr-channels
* Pixel layout illustration:
* [Plane1]: B1 G1 R1 B2 G2 R2 B3 G3 R3 B4 G4 R4
* Data type: 8-bit unsigned integer
*/
"BGR24",
/*
* Channel order: GRAY
* Channel size: full gray-channel
* Pixel layout: planar gray-channel
* Pixel layout illustration:
* [Plane1]: GRAY1 GRAY2 GRAY3 GRAY4
* Data type: 8-bit unsigned integer
*/
"GRAY8",
/*
* Channel order: Y, U, V
* Channel size: full yuv-channels
* Pixel layout: planar yuv-channels
* Pixel layout illustration:
* [Plane1]: Y1 Y2 Y3 Y4
* [Plane2]: U1 U2 U3 U4
* [Plane3]: V1 V2 V3 V4
* Data type: 8-bit unsigned integer
*/
"YUV444P",
/*
* Channel order: Y, U, V
* Channel size: full y-channel, half uv-channels
* Pixel layout: planar yuv-channels
* Pixel layout illustration:
* [Plane1]: Y1 Y2 Y3 Y4
* [Plane2]: U1 U3
* [Plane3]: V1 V3
* Data type: 8-bit unsigned integer
*/
"YUV422P",
/*
* Channel order: Y, U, V
* Channel size: full y-channel, quarter uv-channels
* Pixel layout: planar yuv-channels
* Pixel layout illustration:
* [Plane1]: Y1 Y2 Y3 Y4
* [Plane2]: U1
* [Plane3]: V1
* Data type: 8-bit unsigned integer
*/
"YUV420P",
/*
* Channel order: Y, U, V
* Channel size: full y-channel, quarter uv-channels
* Pixel layout: planar y-channel, interleaving uv-channels
* Pixel layout illustration:
* [Plane1]: Y1 Y2 Y3 Y4
* [Plane2]: U1 V1
* Data type: 8-bit unsigned integer
*/
"YUV420SP_NV12",
/*
* Channel order: Y, V, U
* Channel size: full y-channel, quarter vu-channels
* Pixel layout: planar y-channel, interleaving vu-channels
* Pixel layout illustration:
* [Plane1]: Y1 Y2 Y3 Y4
* [Plane2]: V1 U1
* Data type: 8-bit unsigned integer
*/
"YUV420SP_NV21",
/*
* Channel order: H, S, V
* Channel size: full hsv-channels
* Pixel layout: interleaving hsv-channels
* Pixel layout illustration:
* [Plane1]: H1 S1 V1 H2 S2 V2 H3 S3 V3
* Data type: 32-bit floating point value
*/
"HSV",
/*
* Channel order: l, a, b
* Channel size: full lab-channels
* Pixel layout: interleaving lab-channels
* Pixel layout illustration:
* [Plane1]: l1 a1 b1 l2 a2 b2 l3 a3 b3
* Data type: 32-bit floating point value
*/
"Lab",
/*
* Channel order: DEPTH
* Channel size: full depth-channel
* Pixel layout: planar depth-channel
* Pixel layout illustration:
* [Plane1]: DEPTH1 DEPTH2 DEPTH3 DEPTH4
* Data type: 16-bit unsigned integer
*/
"DEPTH",
};
enum ChannelPixelLayoutDataType {
"uint8",
"int8",
"uint16",
"int16",
"uint32",
"int32",
"float32",
"float64"
};
/*
* Two concepts, ImagePixelLayout and ChannelPixelLayout, together generalize
* the variety of pixel layouts among image formats.
*
* The ChannelPixelLayout represents the pixel layout of a single channel in a
* certain image format and the ImagePixelLayout is just the collection of
* ChannelPixelLayouts. So, the ChannelPixelLayout is defined as a dictionary
* type with properties to describe the layout and the ImagePixelLayout is just
* an alias name to a sequence of ChannelPixelLayout objects.
*
* Since an image format is composed of at least one channel, an
* ImagePixelLayout object contains at least one ChannelPixelLayout object.
*
* Although an image or a video frame is a two-dimensional structure, its data
* is usually stored in a one-dimensional array in the row-major way and the
* ChannelPixelLayout objects use the following properties to describe the
* layout of pixel values in the buffer.
*
* 1) offset:
* denotes the beginning position of the channel's data relative to the
* beginning position of the one-dimensional array.
* 2) width & height:
* denote the width and height of the channel respectively. Each channel in
* an image format may have different height and width.
* 3) data type:
* denotes the format used to store one single pixel value.
* 4) stride:
* the number of bytes between the beginning two consecutive rows in memory.
* (The total bytes of each row plus the padding bytes of each raw.)
* 5) skip value:
* the value is zero for the planar pixel layout, and a positive integer for
* the interleaving pixel layout. (Describes how many bytes there are between
* two adjacent pixel values in this channel.)
*/
/*
* Example1: RGBA image, width = 620, height = 480, stride = 2560
*
* chanel_r: offset = 0, width = 620, height = 480, data type = uint8, stride = 2560, skip = 3
* chanel_g: offset = 1, width = 620, height = 480, data type = uint8, stride = 2560, skip = 3
* chanel_b: offset = 2, width = 620, height = 480, data type = uint8, stride = 2560, skip = 3
* chanel_a: offset = 3, width = 620, height = 480, data type = uint8, stride = 2560, skip = 3
*
* <---------------------------- stride ---------------------------->
* <---------------------- width x 4 ---------------------->
* [index] 01234 8 12 16 20 24 28 2479 2559
* |||||---|---|---|---|---|---|----------------------------|-------|
* [data] RGBARGBARGBARGBARGBAR___R___R... A%%%%%%%%
* [data] RGBARGBARGBARGBARGBAR___R___R... A%%%%%%%%
* [data] RGBARGBARGBARGBARGBAR___R___R... A%%%%%%%%
* ^^^
* r-skip
*/
/*
* Example2: YUV420P image, width = 620, height = 480, stride = 640
*
* chanel_y: offset = 0, width = 620, height = 480, stride = 640, skip = 0
* chanel_u: offset = 307200, width = 310, height = 240, data type = uint8, stride = 320, skip = 0
* chanel_v: offset = 384000, width = 310, height = 240, data type = uint8, stride = 320, skip = 0
*
* <--------------------------- y-stride --------------------------->
* <----------------------- y-width ----------------------->
* [index] 012345 619 639
* ||||||--------------------------------------------------|--------|
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] ......
* <-------- u-stride ---------->
* <----- u-width ----->
* [index] 307200 307509 307519
* |-------------------|--------|
* [data] UUUUUUUUUU... U%%%%%%%%%
* [data] UUUUUUUUUU... U%%%%%%%%%
* [data] UUUUUUUUUU... U%%%%%%%%%
* [data] ......
* <-------- v-stride ---------->
* <- --- v-width ----->
* [index] 384000 384309 384319
* |-------------------|--------|
* [data] VVVVVVVVVV... V%%%%%%%%%
* [data] VVVVVVVVVV... V%%%%%%%%%
* [data] VVVVVVVVVV... V%%%%%%%%%
* [data] ......
*/
/*
* Example3: YUV420SP_NV12 image, width = 620, height = 480, stride = 640
*
* chanel_y: offset = 0, width = 620, height = 480, stride = 640, skip = 0
* chanel_u: offset = 307200, width = 310, height = 240, data type = uint8, stride = 640, skip = 1
* chanel_v: offset = 307201, width = 310, height = 240, data type = uint8, stride = 640, skip = 1
*
* <--------------------------- y-stride -------------------------->
* <----------------------- y-width ---------------------->
* [index] 012345 619 639
* ||||||-------------------------------------------------|--------|
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] YYYYYYYYYYYYYYYYYYYYYYYYYYYYY... Y%%%%%%%%%
* [data] ......
* <--------------------- u-stride / v-stride -------------------->
* <------------------ u-width + v-width ----------------->
* [index] 307200(u-offset) 307819 307839
* |------------------------------------------------------|-------|
* [index] |307201(v-offset) |307820 |
* ||-----------------------------------------------------||------|
* [data] UVUVUVUVUVUVUVUVUVUVUVUVUVUVUV... UV%%%%%%%
* [data] UVUVUVUVUVUVUVUVUVUVUVUVUVUVUV... UV%%%%%%%
* [data] UVUVUVUVUVUVUVUVUVUVUVUVUVUVUV... UV%%%%%%%
* ^ ^
* u-skip v-skip
*/
/*
* Example4: DEPTH image, width = 640, height = 480, stride = 1280
*
* chanel_d: offset = 0, width = 640, height = 480, data type = uint16, stride = 1280, skip = 0
*
* note: each DEPTH value uses two bytes
*
* <----------------------- d-stride ---------------------->
* <----------------------- d-width ----------------------->
* [index] 02468 1278
* |||||---------------------------------------------------|
* [data] DDDDDDDDDDDDDDDDDDDDDDDDDDDDD... D
* [data] DDDDDDDDDDDDDDDDDDDDDDDDDDDDD... D
* [data] DDDDDDDDDDDDDDDDDDDDDDDDDDDDD... D
* [data] ......
*/
dictionary ChannelPixelLayout {
required unsigned long offset;
required unsigned long width;
required unsigned long height;
required ChannelPixelLayoutDataType dataType;
required unsigned long stride;
required unsigned long skip;
};
typedef sequence<ChannelPixelLayout> ImagePixelLayout;
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