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canvas-heightmap

v1.0.7

Published

Canvas heightmap generator

Downloads

16

Readme

canvas-heightmap

npm CI Coverage Status

Canvas Heightmap is a package to get images data by pixels, channels or average in different representations that can be used to build heightmaps.

Quick Start

Install

npm install canvas-heightmap

Use

const ch = new CanvasHeightmap();

// At first set the source and wait until it would be loaded.
ch.use('https://raw.githubusercontent.com/loginov-rocks/canvas-heightmap/master/test/resources/black-and-white.png').
    then(() => {
      // Secondly invoke draw method to render image to be able to get its data.
      ch.draw();
      // Eventually you can get needed data.
      const flatArray = ch.getFlatArray();
      const rgbaArray = ch.getRgbaArray();
    });

API

CanvasHeightmap

Canvas Heightmap class.

Kind: global class


new CanvasHeightmap()

Canvas Heightmap constructor.


use(source)Promise.<HTMLImageElement|HTMLCanvasElement>

Set canvas image source.

Kind: instance method of CanvasHeightmap

| Parameter | Type | | --------- | ------------------------------------------------------------- | | source | string | HTMLImageElement | HTMLCanvasElement |


draw()HTMLCanvasElement

Draw image source on canvas.

Kind: instance method of CanvasHeightmap


getFlatArray([sx], [sy], [sw], [sh])Uint8ClampedArray

Get one-dimensional array containing the data in the RGBA order, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

See:

  • https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/getImageData
  • https://developer.mozilla.org/en-US/docs/Web/API/ImageData/data

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getFlatAverageArray([sx], [sy], [sw], [sh])Uint8ClampedArray

Get one-dimensional array containing the data by pixels with average over RGB channels, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getFlatChannelArray(channel, [sx], [sy], [sw], [sh])Uint8ClampedArray

Get one-dimensional array containing the data for specified channel, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | channel | string | | Channel: red, green, blue or alpha. | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getFlatRgbaArray([sx], [sy], [sw], [sh])Array.<Uint8ClampedArray>

Get two-dimensional array containing the data by pixels and RGBA array for each, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getAverageArray([sx], [sy], [sw], [sh])Array.<Uint8ClampedArray>

Get two-dimensional array containing the rows and cols data by pixels with average over RGB channels, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getChannelArray(channel, [sx], [sy], [sw], [sh])Array.<Uint8ClampedArray>

Get two-dimensional array containing the rows and cols data for specified channel, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | channel | string | | Channel: red, green, blue or alpha. | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |


getRgbaArray([sx], [sy], [sw], [sh])Array.<Array.<Uint8ClampedArray>>

Get three-dimensional array containing the rows and cols data by pixels and RGBA array for each, with integer values between 0 and 255 (included).

Kind: instance method of CanvasHeightmap

| Parameter | Type | Default | Description | | --------- | -------- | -------------- | ------------------------------------------------------------------------------------------------- | | [sx] | number | 0 | The x coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sy] | number | 0 | The y coordinate of the upper left corner of the rectangle from which the data will be extracted. | | [sw] | number | this._width | The width of the rectangle from which the data will be extracted. | | [sh] | number | this._height | The height of the rectangle from which the data will be extracted. |