fabric/dist/src/filters/Contrast.mjs

Object model for HTML5 canvas, and SVG-to-canvas parser. Backed by jsdom and node-canvas.

import { _defineProperty } from "../../_virtual/_@oxc-project_runtime@0.122.0/helpers/defineProperty.mjs";
import { classRegistry } from "../ClassRegistry.mjs";
import { BaseFilter } from "./BaseFilter.mjs";
import { fragmentSource } from "./shaders/constrast.mjs";
//#region src/filters/Contrast.ts
const contrastDefaultValues = { contrast: 0 };
/**
* Contrast filter class
* @example
* const filter = new Contrast({
*   contrast: 0.25
* });
* object.filters.push(filter);
* object.applyFilters();
*/
var Contrast = class extends BaseFilter {
	getFragmentSource() {
		return fragmentSource;
	}
	isNeutralState() {
		return this.contrast === 0;
	}
	/**
	* Apply the Contrast operation to a Uint8Array representing the pixels of an image.
	*
	* @param {Object} options
	* @param {ImageData} options.imageData The Uint8Array to be filtered.
	*/
	applyTo2d({ imageData: { data } }) {
		const contrast = Math.floor(this.contrast * 255), contrastF = 259 * (contrast + 255) / (255 * (259 - contrast));
		for (let i = 0; i < data.length; i += 4) {
			data[i] = contrastF * (data[i] - 128) + 128;
			data[i + 1] = contrastF * (data[i + 1] - 128) + 128;
			data[i + 2] = contrastF * (data[i + 2] - 128) + 128;
		}
	}
	/**
	* Send data from this filter to its shader program's uniforms.
	*
	* @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
	* @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
	*/
	sendUniformData(gl, uniformLocations) {
		gl.uniform1f(uniformLocations.uContrast, this.contrast);
	}
};
_defineProperty(Contrast, "type", "Contrast");
_defineProperty(Contrast, "defaults", contrastDefaultValues);
_defineProperty(Contrast, "uniformLocations", ["uContrast"]);
classRegistry.setClass(Contrast);
//#endregion
export { Contrast };

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