[Libreoffice-commits] online.git: kit/Watermark.hpp
mert (via logerrit)
logerrit at kemper.freedesktop.org
Tue Oct 15 17:26:08 UTC 2019
kit/Watermark.hpp | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 179 insertions(+)
New commits:
commit a1c58c04cc502addd4e1a07215867e44f075f48b
Author: mert <mert.tumer at collabora.com>
AuthorDate: Tue Oct 15 20:25:26 2019 +0300
Commit: mert <mert.tumer at collabora.com>
CommitDate: Tue Oct 15 20:25:26 2019 +0300
Added Watermark.hpp
Change-Id: I3619283031865f59f94157d5b8df14a94ac9327b
diff --git a/kit/Watermark.hpp b/kit/Watermark.hpp
new file mode 100644
index 000000000..830023f43
--- /dev/null
+++ b/kit/Watermark.hpp
@@ -0,0 +1,179 @@
+#ifndef INCLUDED_WATERMARK_HPP
+#define INCLUDED_WATERMARK_HPP
+
+#define LOK_USE_UNSTABLE_API
+#include <LibreOfficeKit/LibreOfficeKitInit.h>
+#include <LibreOfficeKit/LibreOfficeKit.hxx>
+#include <LibreOfficeKit/LibreOfficeKitEnums.h>
+#include <vector>
+#include <Log.hpp>
+#include <cstdlib>
+#include <string>
+#include "ChildSession.hpp"
+
+class Watermark
+{
+public:
+ Watermark(const std::shared_ptr<lok::Document>& loKitDoc,
+ const std::shared_ptr<ChildSession> & session)
+ : _loKitDoc(loKitDoc)
+ , _text(session->getWatermarkText())
+ , _font("Liberation Sans")
+ , _width(0)
+ , _height(0)
+ , _alphaLevel(session->getWatermarkOpacity())
+ {
+ }
+
+ ~Watermark()
+ {
+ }
+
+ void blending(unsigned char* tilePixmap,
+ int offsetX, int offsetY,
+ int tilesPixmapWidth, int tilesPixmapHeight,
+ int tileWidth, int tileHeight,
+ LibreOfficeKitTileMode /*mode*/)
+ {
+ // set requested watermark size a little bit smaller than tile size
+ int width = tileWidth * 0.9;
+ int height = tileHeight * 0.9;
+
+ const std::vector<unsigned char>* pixmap = getPixmap(width, height);
+
+ if (pixmap && tilePixmap)
+ {
+ // center watermark
+ const int maxX = std::min(tileWidth, _width);
+ const int maxY = std::min(tileHeight, _height);
+ offsetX += (tileWidth - maxX) / 2;
+ offsetY += (tileHeight - maxY) / 2;
+
+ alphaBlend(*pixmap, _width, _height, offsetX, offsetY, tilePixmap, tilesPixmapWidth, tilesPixmapHeight);
+ }
+ }
+
+private:
+ /// Alpha blend pixels from 'from' over the 'to'.
+ void alphaBlend(const std::vector<unsigned char>& from, int from_width, int from_height, int from_offset_x, int from_offset_y,
+ unsigned char* to, int to_width, int to_height)
+ {
+ for (int to_y = from_offset_y, from_y = 0; (to_y < to_height) && (from_y < from_height) ; ++to_y, ++from_y)
+ for (int to_x = from_offset_x, from_x = 0; (to_x < to_width) && (from_x < from_width); ++to_x, ++from_x)
+ {
+ const unsigned char* f = from.data() + 4 * (from_y * from_width + from_x);
+ double src_r = f[0];
+ double src_g = f[1];
+ double src_b = f[2];
+ double src_a = f[3] / 255.0;
+
+ unsigned char* t = to + 4 * (to_y * to_width + to_x);
+ double dst_r = t[0];
+ double dst_g = t[1];
+ double dst_b = t[2];
+ double dst_a = t[3] / 255.0;
+
+ double out_a = src_a + dst_a * (1.0 - src_a);
+ unsigned char out_r = src_r + dst_r * (1.0 - src_a);
+ unsigned char out_g = src_g + dst_g * (1.0 - src_a);
+ unsigned char out_b = src_b + dst_b * (1.0 - src_a);
+
+ t[0] = out_r;
+ t[1] = out_g;
+ t[2] = out_b;
+ t[3] = static_cast<unsigned char>(out_a * 255.0);
+ }
+ }
+
+ /// Create bitmap that we later use as the watermark for every tile.
+ const std::vector<unsigned char>* getPixmap(int width, int height)
+ {
+ if (!_pixmap.empty() && width == _width && height == _height)
+ return &_pixmap;
+
+ _pixmap.clear();
+
+ _width = width;
+ _height = height;
+
+ if (!_loKitDoc)
+ {
+ LOG_ERR("Watermark rendering requested without a valid document.");
+ return nullptr;
+ }
+
+ // renderFont returns a buffer based on RGBA mode, where r, g, b
+ // are always set to 0 (black) and the alpha level is 0 everywhere
+ // except on the text area; the alpha level take into account of
+ // performing anti-aliasing over the text edges.
+ unsigned char* textPixels = _loKitDoc->renderFont(_font.c_str(), _text.c_str(), &_width, &_height);
+
+ if (!textPixels)
+ {
+ LOG_ERR("Watermark: rendering failed.");
+ }
+
+ const unsigned int pixel_count = width * height * 4;
+
+ std::vector<unsigned char> text(textPixels, textPixels + pixel_count);
+ // No longer needed.
+ std::free(textPixels);
+
+ _pixmap.reserve(pixel_count);
+
+ // Create the white blurred background
+ // Use box blur, it's enough for our purposes
+ const int r = 2;
+ const double weight = (r+1) * (r+1);
+ for (int y = 0; y < height; ++y)
+ {
+ for (int x = 0; x < width; ++x)
+ {
+ double t = 0;
+ for (int ky = std::max(y - r, 0); ky <= std::min(y + r, height - 1); ++ky)
+ {
+ for (int kx = std::max(x - r, 0); kx <= std::min(x + r, width - 1); ++kx)
+ {
+ // Pre-multiplied alpha; the text is black, so all the
+ // information is only in the alpha channel
+ t += text[4 * (ky * width + kx) + 3];
+ }
+ }
+
+ // Clamp the result.
+ double avg = t / weight;
+ if (avg > 255.0)
+ avg = 255.0;
+
+ // Pre-multiplied alpha, but use white for the resulting color
+ const double alpha = avg / 255.0;
+ _pixmap[4 * (y * width + x) + 0] = 0xff * alpha;
+ _pixmap[4 * (y * width + x) + 1] = 0xff * alpha;
+ _pixmap[4 * (y * width + x) + 2] = 0xff * alpha;
+ _pixmap[4 * (y * width + x) + 3] = avg;
+ }
+ }
+
+ // Now copy the (black) text over the (white) blur
+ alphaBlend(text, _width, _height, 0, 0, _pixmap.data(), _width, _height);
+
+ // Make the resulting pixmap semi-transparent
+ for (unsigned char* p = _pixmap.data(); p < _pixmap.data() + pixel_count; p++)
+ {
+ *p = static_cast<unsigned char>(*p * _alphaLevel);
+ }
+
+ return &_pixmap;
+ }
+
+private:
+ std::shared_ptr<lok::Document> _loKitDoc;
+ std::string _text;
+ std::string _font;
+ int _width;
+ int _height;
+ double _alphaLevel;
+ std::vector<unsigned char> _pixmap;
+};
+
+#endif
\ No newline at end of file
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