Snapper, some code for screenshot tool

PdfForQtLib/sources/pdfwidgetutils.cpp

@@ -0,0 +1,79 @@
+//    Copyright (C) 2019-2020 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "pdfwidgetutils.h"
+
+#ifdef Q_OS_MAC
+int qt_default_dpi_x() { return 72; }
+int qt_default_dpi_y() { return 72; }
+#else
+int qt_default_dpi_x() { return 96; }
+int qt_default_dpi_y() { return 96; }
+#endif
+
+namespace pdf
+{
+
+int PDFWidgetUtils::getPixelSize(QPaintDevice* device, pdf::PDFReal sizeMM)
+{
+    const int width = device->width();
+    const int height = device->height();
+
+    if (width > height)
+    {
+        return PDFReal(width) * sizeMM / PDFReal(device->widthMM());
+    }
+    else
+    {
+        return PDFReal(height) * sizeMM / PDFReal(device->heightMM());
+    }
+}
+
+int PDFWidgetUtils::scaleDPI_x(QPaintDevice* device, int unscaledSize)
+{
+    const double logicalDPI_x = device->logicalDpiX();
+    const double defaultDPI_x = qt_default_dpi_x();
+    return (logicalDPI_x / defaultDPI_x) * unscaledSize;
+}
+
+void PDFWidgetUtils::scaleWidget(QWidget* widget, QSize unscaledSize)
+{
+    const double logicalDPI_x = widget->logicalDpiX();
+    const double logicalDPI_y = widget->logicalDpiY();
+    const double defaultDPI_x = qt_default_dpi_x();
+    const double defaultDPI_y = qt_default_dpi_y();
+
+    const int width = (logicalDPI_x / defaultDPI_x) * unscaledSize.width();
+    const int height = (logicalDPI_y / defaultDPI_y) * unscaledSize.height();
+
+    widget->resize(width, height);
+}
+
+QSize PDFWidgetUtils::scaleDPI(QPaintDevice* widget, QSize unscaledSize)
+{
+    const double logicalDPI_x = widget->logicalDpiX();
+    const double logicalDPI_y = widget->logicalDpiY();
+    const double defaultDPI_x = qt_default_dpi_x();
+    const double defaultDPI_y = qt_default_dpi_y();
+
+    const int width = (logicalDPI_x / defaultDPI_x) * unscaledSize.width();
+    const int height = (logicalDPI_y / defaultDPI_y) * unscaledSize.height();
+
+    return QSize(width, height);
+}
+
+} // namespace pdf