/**
* StackBlur - a fast almost Gaussian Blur For Canvas
*
* In case you find this class useful - especially in commercial projects -
* I am not totally unhappy for a small donation to my PayPal account
* mario@quasimondo.de
*
* Or support me on flattr:
* {@link https://flattr.com/thing/72791/StackBlur-a-fast-almost-Gaussian-Blur-Effect-for-CanvasJavascript}
* @module StackBlur
* @version 0.5
* @author Mario Klingemann
* Contact: mario@quasimondo.com
* Website: {@link http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html}
* Twitter: @quasimondo
*
* @copyright (c) 2010 Mario Klingemann
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
const mulTable = [512, 512, 456, 512, 328, 456, 335, 512, 405, 328, 271, 456, 388, 335, 292, 512, 454, 405, 364, 328, 298, 271, 496, 456, 420, 388, 360, 335, 312, 292, 273, 512, 482, 454, 428, 405, 383, 364, 345, 328, 312, 298, 284, 271, 259, 496, 475, 456, 437, 420, 404, 388, 374, 360, 347, 335, 323, 312, 302, 292, 282, 273, 265, 512, 497, 482, 468, 454, 441, 428, 417, 405, 394, 383, 373, 364, 354, 345, 337, 328, 320, 312, 305, 298, 291, 284, 278, 271, 265, 259, 507, 496, 485, 475, 465, 456, 446, 437, 428, 420, 412, 404, 396, 388, 381, 374, 367, 360, 354, 347, 341, 335, 329, 323, 318, 312, 307, 302, 297, 292, 287, 282, 278, 273, 269, 265, 261, 512, 505, 497, 489, 482, 475, 468, 461, 454, 447, 441, 435, 428, 422, 417, 411, 405, 399, 394, 389, 383, 378, 373, 368, 364, 359, 354, 350, 345, 341, 337, 332, 328, 324, 320, 316, 312, 309, 305, 301, 298, 294, 291, 287, 284, 281, 278, 274, 271, 268, 265, 262, 259, 257, 507, 501, 496, 491, 485, 480, 475, 470, 465, 460, 456, 451, 446, 442, 437, 433, 428, 424, 420, 416, 412, 408, 404, 400, 396, 392, 388, 385, 381, 377, 374, 370, 367, 363, 360, 357, 354, 350, 347, 344, 341, 338, 335, 332, 329, 326, 323, 320, 318, 315, 312, 310, 307, 304, 302, 299, 297, 294, 292, 289, 287, 285, 282, 280, 278, 275, 273, 271, 269, 267, 265, 263, 261, 259];
const shgTable = [9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24];
/**
 * @param {string|HTMLImageElement} img
 * @param {string|HTMLCanvasElement} canvas
 * @param {Float} radius
 * @param {boolean} blurAlphaChannel
 * @returns {undefined}
 */

function processImage(img, canvas, radius, blurAlphaChannel) {
  if (typeof img === 'string') {
    img = document.getElementById(img);
  }

  if (!img || !('naturalWidth' in img)) {
    return;
  }

  const w = img.naturalWidth;
  const h = img.naturalHeight;

  if (typeof canvas === 'string') {
    canvas = document.getElementById(canvas);
  }

  if (!canvas || !('getContext' in canvas)) {
    return;
  }

  canvas.style.width = w + 'px';
  canvas.style.height = h + 'px';
  canvas.width = w;
  canvas.height = h;
  const context = canvas.getContext('2d');
  context.clearRect(0, 0, w, h);
  context.drawImage(img, 0, 0);

  if (isNaN(radius) || radius < 1) {
    return;
  }

  if (blurAlphaChannel) {
    processCanvasRGBA(canvas, 0, 0, w, h, radius);
  } else {
    processCanvasRGB(canvas, 0, 0, w, h, radius);
  }
}
/**
 * @param {string|HTMLCanvasElement} canvas
 * @param {Integer} topX
 * @param {Integer} topY
 * @param {Integer} width
 * @param {Integer} height
 * @throws {Error}
 * @returns {ImageData} See {@link https://html.spec.whatwg.org/multipage/canvas.html#imagedata}
 */


function getImageDataFromCanvas(canvas, topX, topY, width, height) {
  if (typeof canvas === 'string') {
    canvas = document.getElementById(canvas);
  }

  if (!canvas || !('getContext' in canvas)) {
    return;
  }

  const context = canvas.getContext('2d');

  try {
    return context.getImageData(topX, topY, width, height);
  } catch (e) {
    throw new Error('unable to access image data: ' + e);
  }
}
/**
 * @param {HTMLCanvasElement} canvas
 * @param {Integer} topX
 * @param {Integer} topY
 * @param {Integer} width
 * @param {Integer} height
 * @param {Float} radius
 * @returns {undefined}
 */


function processCanvasRGBA(canvas, topX, topY, width, height, radius) {
  if (isNaN(radius) || radius < 1) {
    return;
  }

  radius |= 0;
  let imageData = getImageDataFromCanvas(canvas, topX, topY, width, height);
  imageData = processImageDataRGBA(imageData, topX, topY, width, height, radius);
  canvas.getContext('2d').putImageData(imageData, topX, topY);
}
/**
 * @param {ImageData} imageData
 * @param {Integer} topX
 * @param {Integer} topY
 * @param {Integer} width
 * @param {Integer} height
 * @param {Float} radius
 * @returns {ImageData}
 */


function processImageDataRGBA(imageData, topX, topY, width, height, radius) {
  const pixels = imageData.data;
  let x, y, i, p, yp, yi, yw, rSum, gSum, bSum, aSum, rOutSum, gOutSum, bOutSum, aOutSum, rInSum, gInSum, bInSum, aInSum, pr, pg, pb, pa, rbs;
  const div = radius + radius + 1; // const w4 = width << 2;

  const widthMinus1 = width - 1;
  const heightMinus1 = height - 1;
  const radiusPlus1 = radius + 1;
  const sumFactor = radiusPlus1 * (radiusPlus1 + 1) / 2;
  const stackStart = new BlurStack();
  let stack = stackStart;
  let stackEnd;

  for (i = 1; i < div; i++) {
    stack = stack.next = new BlurStack();

    if (i === radiusPlus1) {
      stackEnd = stack;
    }
  }

  stack.next = stackStart;
  let stackIn = null;
  let stackOut = null;
  yw = yi = 0;
  const mulSum = mulTable[radius];
  const shgSum = shgTable[radius];

  for (y = 0; y < height; y++) {
    rInSum = gInSum = bInSum = aInSum = rSum = gSum = bSum = aSum = 0;
    rOutSum = radiusPlus1 * (pr = pixels[yi]);
    gOutSum = radiusPlus1 * (pg = pixels[yi + 1]);
    bOutSum = radiusPlus1 * (pb = pixels[yi + 2]);
    aOutSum = radiusPlus1 * (pa = pixels[yi + 3]);
    rSum += sumFactor * pr;
    gSum += sumFactor * pg;
    bSum += sumFactor * pb;
    aSum += sumFactor * pa;
    stack = stackStart;

    for (i = 0; i < radiusPlus1; i++) {
      stack.r = pr;
      stack.g = pg;
      stack.b = pb;
      stack.a = pa;
      stack = stack.next;
    }

    for (i = 1; i < radiusPlus1; i++) {
      p = yi + ((widthMinus1 < i ? widthMinus1 : i) << 2);
      rSum += (stack.r = pr = pixels[p]) * (rbs = radiusPlus1 - i);
      gSum += (stack.g = pg = pixels[p + 1]) * rbs;
      bSum += (stack.b = pb = pixels[p + 2]) * rbs;
      aSum += (stack.a = pa = pixels[p + 3]) * rbs;
      rInSum += pr;
      gInSum += pg;
      bInSum += pb;
      aInSum += pa;
      stack = stack.next;
    }

    stackIn = stackStart;
    stackOut = stackEnd;

    for (x = 0; x < width; x++) {
      pixels[yi + 3] = pa = aSum * mulSum >> shgSum;

      if (pa !== 0) {
        pa = 255 / pa;
        pixels[yi] = (rSum * mulSum >> shgSum) * pa;
        pixels[yi + 1] = (gSum * mulSum >> shgSum) * pa;
        pixels[yi + 2] = (bSum * mulSum >> shgSum) * pa;
      } else {
        pixels[yi] = pixels[yi + 1] = pixels[yi + 2] = 0;
      }

      rSum -= rOutSum;
      gSum -= gOutSum;
      bSum -= bOutSum;
      aSum -= aOutSum;
      rOutSum -= stackIn.r;
      gOutSum -= stackIn.g;
      bOutSum -= stackIn.b;
      aOutSum -= stackIn.a;
      p = yw + ((p = x + radius + 1) < widthMinus1 ? p : widthMinus1) << 2;
      rInSum += stackIn.r = pixels[p];
      gInSum += stackIn.g = pixels[p + 1];
      bInSum += stackIn.b = pixels[p + 2];
      aInSum += stackIn.a = pixels[p + 3];
      rSum += rInSum;
      gSum += gInSum;
      bSum += bInSum;
      aSum += aInSum;
      stackIn = stackIn.next;
      rOutSum += pr = stackOut.r;
      gOutSum += pg = stackOut.g;
      bOutSum += pb = stackOut.b;
      aOutSum += pa = stackOut.a;
      rInSum -= pr;
      gInSum -= pg;
      bInSum -= pb;
      aInSum -= pa;
      stackOut = stackOut.next;
      yi += 4;
    }

    yw += width;
  }

  for (x = 0; x < width; x++) {
    gInSum = bInSum = aInSum = rInSum = gSum = bSum = aSum = rSum = 0;
    yi = x << 2;
    rOutSum = radiusPlus1 * (pr = pixels[yi]);
    gOutSum = radiusPlus1 * (pg = pixels[yi + 1]);
    bOutSum = radiusPlus1 * (pb = pixels[yi + 2]);
    aOutSum = radiusPlus1 * (pa = pixels[yi + 3]);
    rSum += sumFactor * pr;
    gSum += sumFactor * pg;
    bSum += sumFactor * pb;
    aSum += sumFactor * pa;
    stack = stackStart;

    for (i = 0; i < radiusPlus1; i++) {
      stack.r = pr;
      stack.g = pg;
      stack.b = pb;
      stack.a = pa;
      stack = stack.next;
    }

    yp = width;

    for (i = 1; i <= radius; i++) {
      yi = yp + x << 2;
      rSum += (stack.r = pr = pixels[yi]) * (rbs = radiusPlus1 - i);
      gSum += (stack.g = pg = pixels[yi + 1]) * rbs;
      bSum += (stack.b = pb = pixels[yi + 2]) * rbs;
      aSum += (stack.a = pa = pixels[yi + 3]) * rbs;
      rInSum += pr;
      gInSum += pg;
      bInSum += pb;
      aInSum += pa;
      stack = stack.next;

      if (i < heightMinus1) {
        yp += width;
      }
    }

    yi = x;
    stackIn = stackStart;
    stackOut = stackEnd;

    for (y = 0; y < height; y++) {
      p = yi << 2;
      pixels[p + 3] = pa = aSum * mulSum >> shgSum;

      if (pa > 0) {
        pa = 255 / pa;
        pixels[p] = (rSum * mulSum >> shgSum) * pa;
        pixels[p + 1] = (gSum * mulSum >> shgSum) * pa;
        pixels[p + 2] = (bSum * mulSum >> shgSum) * pa;
      } else {
        pixels[p] = pixels[p + 1] = pixels[p + 2] = 0;
      }

      rSum -= rOutSum;
      gSum -= gOutSum;
      bSum -= bOutSum;
      aSum -= aOutSum;
      rOutSum -= stackIn.r;
      gOutSum -= stackIn.g;
      bOutSum -= stackIn.b;
      aOutSum -= stackIn.a;
      p = x + ((p = y + radiusPlus1) < heightMinus1 ? p : heightMinus1) * width << 2;
      rSum += rInSum += stackIn.r = pixels[p];
      gSum += gInSum += stackIn.g = pixels[p + 1];
      bSum += bInSum += stackIn.b = pixels[p + 2];
      aSum += aInSum += stackIn.a = pixels[p + 3];
      stackIn = stackIn.next;
      rOutSum += pr = stackOut.r;
      gOutSum += pg = stackOut.g;
      bOutSum += pb = stackOut.b;
      aOutSum += pa = stackOut.a;
      rInSum -= pr;
      gInSum -= pg;
      bInSum -= pb;
      aInSum -= pa;
      stackOut = stackOut.next;
      yi += width;
    }
  }

  return imageData;
}
/**
 * @param {HTMLCanvasElement} canvas
 * @param {Integer} topX
 * @param {Integer} topY
 * @param {Integer} width
 * @param {Integer} height
 * @param {Float} radius
 * @returns {undefined}
 */


function processCanvasRGB(canvas, topX, topY, width, height, radius) {
  if (isNaN(radius) || radius < 1) {
    return;
  }

  radius |= 0;
  let imageData = getImageDataFromCanvas(canvas, topX, topY, width, height);
  imageData = processImageDataRGB(imageData, topX, topY, width, height, radius);
  canvas.getContext('2d').putImageData(imageData, topX, topY);
}
/**
 * @param {ImageData} imageData
 * @param {Integer} topX
 * @param {Integer} topY
 * @param {Integer} width
 * @param {Integer} height
 * @param {Float} radius
 * @returns {ImageData}
 */


function processImageDataRGB(imageData, topX, topY, width, height, radius) {
  const pixels = imageData.data;
  let x, y, i, p, yp, yi, yw, rSum, gSum, bSum, rOutSum, gOutSum, bOutSum, rInSum, gInSum, bInSum, pr, pg, pb, rbs;
  const div = radius + radius + 1; // const w4 = width << 2;

  const widthMinus1 = width - 1;
  const heightMinus1 = height - 1;
  const radiusPlus1 = radius + 1;
  const sumFactor = radiusPlus1 * (radiusPlus1 + 1) / 2;
  const stackStart = new BlurStack();
  let stack = stackStart;
  let stackEnd;

  for (i = 1; i < div; i++) {
    stack = stack.next = new BlurStack();

    if (i === radiusPlus1) {
      stackEnd = stack;
    }
  }

  stack.next = stackStart;
  let stackIn = null;
  let stackOut = null;
  yw = yi = 0;
  const mulSum = mulTable[radius];
  const shgSum = shgTable[radius];

  for (y = 0; y < height; y++) {
    rInSum = gInSum = bInSum = rSum = gSum = bSum = 0;
    rOutSum = radiusPlus1 * (pr = pixels[yi]);
    gOutSum = radiusPlus1 * (pg = pixels[yi + 1]);
    bOutSum = radiusPlus1 * (pb = pixels[yi + 2]);
    rSum += sumFactor * pr;
    gSum += sumFactor * pg;
    bSum += sumFactor * pb;
    stack = stackStart;

    for (i = 0; i < radiusPlus1; i++) {
      stack.r = pr;
      stack.g = pg;
      stack.b = pb;
      stack = stack.next;
    }

    for (i = 1; i < radiusPlus1; i++) {
      p = yi + ((widthMinus1 < i ? widthMinus1 : i) << 2);
      rSum += (stack.r = pr = pixels[p]) * (rbs = radiusPlus1 - i);
      gSum += (stack.g = pg = pixels[p + 1]) * rbs;
      bSum += (stack.b = pb = pixels[p + 2]) * rbs;
      rInSum += pr;
      gInSum += pg;
      bInSum += pb;
      stack = stack.next;
    }

    stackIn = stackStart;
    stackOut = stackEnd;

    for (x = 0; x < width; x++) {
      pixels[yi] = rSum * mulSum >> shgSum;
      pixels[yi + 1] = gSum * mulSum >> shgSum;
      pixels[yi + 2] = bSum * mulSum >> shgSum;
      rSum -= rOutSum;
      gSum -= gOutSum;
      bSum -= bOutSum;
      rOutSum -= stackIn.r;
      gOutSum -= stackIn.g;
      bOutSum -= stackIn.b;
      p = yw + ((p = x + radius + 1) < widthMinus1 ? p : widthMinus1) << 2;
      rInSum += stackIn.r = pixels[p];
      gInSum += stackIn.g = pixels[p + 1];
      bInSum += stackIn.b = pixels[p + 2];
      rSum += rInSum;
      gSum += gInSum;
      bSum += bInSum;
      stackIn = stackIn.next;
      rOutSum += pr = stackOut.r;
      gOutSum += pg = stackOut.g;
      bOutSum += pb = stackOut.b;
      rInSum -= pr;
      gInSum -= pg;
      bInSum -= pb;
      stackOut = stackOut.next;
      yi += 4;
    }

    yw += width;
  }

  for (x = 0; x < width; x++) {
    gInSum = bInSum = rInSum = gSum = bSum = rSum = 0;
    yi = x << 2;
    rOutSum = radiusPlus1 * (pr = pixels[yi]);
    gOutSum = radiusPlus1 * (pg = pixels[yi + 1]);
    bOutSum = radiusPlus1 * (pb = pixels[yi + 2]);
    rSum += sumFactor * pr;
    gSum += sumFactor * pg;
    bSum += sumFactor * pb;
    stack = stackStart;

    for (i = 0; i < radiusPlus1; i++) {
      stack.r = pr;
      stack.g = pg;
      stack.b = pb;
      stack = stack.next;
    }

    yp = width;

    for (i = 1; i <= radius; i++) {
      yi = yp + x << 2;
      rSum += (stack.r = pr = pixels[yi]) * (rbs = radiusPlus1 - i);
      gSum += (stack.g = pg = pixels[yi + 1]) * rbs;
      bSum += (stack.b = pb = pixels[yi + 2]) * rbs;
      rInSum += pr;
      gInSum += pg;
      bInSum += pb;
      stack = stack.next;

      if (i < heightMinus1) {
        yp += width;
      }
    }

    yi = x;
    stackIn = stackStart;
    stackOut = stackEnd;

    for (y = 0; y < height; y++) {
      p = yi << 2;
      pixels[p] = rSum * mulSum >> shgSum;
      pixels[p + 1] = gSum * mulSum >> shgSum;
      pixels[p + 2] = bSum * mulSum >> shgSum;
      rSum -= rOutSum;
      gSum -= gOutSum;
      bSum -= bOutSum;
      rOutSum -= stackIn.r;
      gOutSum -= stackIn.g;
      bOutSum -= stackIn.b;
      p = x + ((p = y + radiusPlus1) < heightMinus1 ? p : heightMinus1) * width << 2;
      rSum += rInSum += stackIn.r = pixels[p];
      gSum += gInSum += stackIn.g = pixels[p + 1];
      bSum += bInSum += stackIn.b = pixels[p + 2];
      stackIn = stackIn.next;
      rOutSum += pr = stackOut.r;
      gOutSum += pg = stackOut.g;
      bOutSum += pb = stackOut.b;
      rInSum -= pr;
      gInSum -= pg;
      bInSum -= pb;
      stackOut = stackOut.next;
      yi += width;
    }
  }

  return imageData;
}
/**
 *
 */


class BlurStack {
  constructor() {
    this.r = 0;
    this.g = 0;
    this.b = 0;
    this.a = 0;
    this.next = null;
  }

}

export { BlurStack, processImage as image, processCanvasRGBA as canvasRGBA, processCanvasRGB as canvasRGB, processImageDataRGBA as imageDataRGBA, processImageDataRGB as imageDataRGB };