7183a3d3de
Change-Id: Ice934380029bf27054e830fffc07a5d037d1430f Signed-off-by: Michael Meeks <michael.meeks@collabora.com>
228 lines
8.4 KiB
C++
228 lines
8.4 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* Copyright the Collabora Online contributors.
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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#define LOK_USE_UNSTABLE_API
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#include <LibreOfficeKit/LibreOfficeKitInit.h>
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#include <LibreOfficeKit/LibreOfficeKit.hxx>
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#include <LibreOfficeKit/LibreOfficeKitEnums.h>
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#include <vector>
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#include <Log.hpp>
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#include <cstdlib>
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#include <string>
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#include <cmath>
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#include <unordered_map>
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class Watermark final
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{
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public:
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Watermark(const std::shared_ptr<lok::Document>& loKitDoc, const std::string& text,
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double opacity)
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: _loKitDoc(loKitDoc)
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, _text(Util::replace(text, "\\n", "\n"))
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, _font("Carlito")
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, _alphaLevel(opacity)
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{
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if (_loKitDoc == nullptr)
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{
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LOG_ERR("Watermark rendering requested without a valid document. Watermarking will be disabled.");
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assert(_loKitDoc && "Valid loKitDoc is required for Watermark.");
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}
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}
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void blending(unsigned char* tilePixmap,
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int offsetX, int offsetY,
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int tilesPixmapWidth, int tilesPixmapHeight,
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int tileWidth, int tileHeight,
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LibreOfficeKitTileMode /*mode*/)
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{
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// set requested watermark size a little bit smaller than tile size
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const int width = tileWidth * 0.8;
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const int height = tileHeight * 0.8;
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const std::vector<unsigned char>* pixmap = getPixmap(width, height);
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if (pixmap && tilePixmap)
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{
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// center watermark
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const int maxX = std::min(tileWidth, width);
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const int maxY = std::min(tileHeight, height);
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offsetX += (tileWidth - maxX) / 2;
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offsetY += (tileHeight - maxY) / 2;
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alphaBlend(*pixmap, width, height, offsetX, offsetY, tilePixmap, tilesPixmapWidth, tilesPixmapHeight, false);
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}
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}
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private:
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/// Alpha blend pixels from 'from' over the 'to'.
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void alphaBlend(const std::vector<unsigned char>& from, int from_width, int from_height, int from_offset_x, int from_offset_y,
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unsigned char* to, int to_width, int to_height, const bool isFontBlending)
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{
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bool isCalc = (_loKitDoc->getDocumentType() == LOK_DOCTYPE_SPREADSHEET);
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for (int to_y = from_offset_y, from_y = 0; (to_y < to_height) && (from_y < from_height) ; ++to_y, ++from_y)
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for (int to_x = from_offset_x, from_x = 0; (to_x < to_width) && (from_x < from_width); ++to_x, ++from_x)
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{
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unsigned char* t = to + 4 * (to_y * to_width + to_x);
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if (!isFontBlending && !isCalc && t[3] != 255)
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continue;
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double dst_r = t[0];
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double dst_g = t[1];
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double dst_b = t[2];
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double dst_a = t[3] / 255.0;
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const unsigned char* f = from.data() + 4 * (from_y * from_width + from_x);
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double src_r = f[0];
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double src_g = f[1];
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double src_b = f[2];
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double src_a = f[3] / 255.0;
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double out_a = src_a + dst_a * (1.0 - src_a);
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unsigned char out_r = src_r + dst_r * (1.0 - src_a);
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unsigned char out_g = src_g + dst_g * (1.0 - src_a);
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unsigned char out_b = src_b + dst_b * (1.0 - src_a);
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t[0] = out_r;
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t[1] = out_g;
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t[2] = out_b;
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t[3] = static_cast<unsigned char>(out_a * 255.0);
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}
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}
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/// Create bitmap that we later use as the watermark for every tile.
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const std::vector<unsigned char>* getPixmap(int width, int height)
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{
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if (_loKitDoc == nullptr)
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{
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return nullptr;
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}
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const size_t key = width + height * 10000;
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if (_pixmaps.find(key) != _pixmaps.end())
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{
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return &_pixmaps[key];
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}
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// renderFont returns a buffer based on RGBA mode, where r, g, b
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// are always set to 0 (black) and the alpha level is 0 everywhere
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// except on the text area; the alpha level take into account of
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// performing anti-aliasing over the text edges.
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unsigned char* textPixels = _loKitDoc->renderFont(_font.c_str(), _text.c_str(), &width, &height, 0);
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if (!textPixels)
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{
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LOG_ERR("Watermark: rendering failed.");
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return nullptr;
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}
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const unsigned int pixel_count = width * height * 4;
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std::vector<unsigned char> text(textPixels, textPixels + pixel_count);
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// No longer needed.
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std::free(textPixels);
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_pixmaps.emplace(key, std::vector<unsigned char>(pixel_count));
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std::vector<unsigned char>& _pixmap = _pixmaps[key];
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/*
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apply 2d rotation transformation (counter-clockwise):
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| cos(a) -sin(a) | | x |
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| sin(a) cos(a) | | y |
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*/
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// Create the white blurred background
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// Use box blur, it's enough for our purposes
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// PI / 4 (45 degrees): sin = cos = 1/sqrt(2)
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const double sin = 0.707106781186547524;
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const double cos = sin;
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const double x0 = width / 2.0;
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const double y0 = height / 2.0;
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std::vector<unsigned char> _rotatedText(pixel_count);
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const int r = 2;
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const double weight = (r+1) * (r+1);
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for (int y = 0; y < height; ++y)
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{
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for (int x = 0; x < width; ++x)
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{
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// move origin to the center
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const double fx = x - x0;
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const double fy = y - y0;
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const int rX = (fx * cos) - (fy * sin) + x0;
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const int rY = (fx * sin) + (fy * cos) + y0;
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const unsigned int pPos = 4 * (rY * width + rX);
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if (rX >= 0 && rX <= width && rY >= 0 && rY <= height && pPos < text.size())
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{
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unsigned char* p = text.data() + 4 * (rY * width + rX);
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_rotatedText[4 * (y * width + x) + 0] = p[0];
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_rotatedText[4 * (y * width + x) + 1] = p[1];
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_rotatedText[4 * (y * width + x) + 2] = p[2];
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_rotatedText[4 * (y * width + x) + 3] = p[3];
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}
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else
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{
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_rotatedText[4 * (y * width + x) + 0] = 0.0;
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_rotatedText[4 * (y * width + x) + 1] = 0.0;
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_rotatedText[4 * (y * width + x) + 2] = 0.0;
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_rotatedText[4 * (y * width + x) + 3] = 0.0;
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}
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double t = 0;
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for (int ky = std::max(rY - r, 0); ky <= std::min(rY + r, height - 1); ++ky)
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{
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for (int kx = std::max(rX - r, 0); kx <= std::min(rX + r, width - 1); ++kx)
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{
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// Pre-multiplied alpha; the text is black, so all the
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// information is only in the alpha channel
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t += text[4 * (ky * width + kx) + 3];
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}
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}
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// Clamp the result.
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double avg = t / weight;
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if (avg > 255.0)
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avg = 255.0;
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// Pre-multiplied alpha, but use white for the resulting color
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const double alpha = avg / 255.0;
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_pixmap[4 * (y * width + x) + 0] = 0xff * alpha;
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_pixmap[4 * (y * width + x) + 1] = 0xff * alpha;
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_pixmap[4 * (y * width + x) + 2] = 0xff * alpha;
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_pixmap[4 * (y * width + x) + 3] = avg;
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}
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}
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// Now copy the (black) text over the (white) blur
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alphaBlend(_rotatedText, width, height, 0, 0, _pixmap.data(), width, height, true);
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// Make the resulting pixmap semi-transparent
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for (unsigned char* p = _pixmap.data(); p < _pixmap.data() + pixel_count; p++)
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{
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*p = static_cast<unsigned char>(*p * _alphaLevel);
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}
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return &_pixmap;
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}
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private:
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const std::shared_ptr<lok::Document> _loKitDoc;
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const std::string _text;
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const std::string _font;
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const double _alphaLevel;
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std::unordered_map<size_t, std::vector<unsigned char>> _pixmaps;
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};
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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