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37 lines
1.1 KiB
C++
37 lines
1.1 KiB
C++
#include <QPainter>
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#include "image.h"
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#define TILE_SIZE 256
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#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
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#define OPENGL_SIZE_LIMIT 536870912 /* 512MB */
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#else
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#define OPENGL_SIZE_LIMIT 134217728 /* 128MB */
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#endif
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void Image::draw(QPainter *painter, const QRectF &rect, Map::Flags flags)
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{
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qreal ratio = _img.devicePixelRatioF();
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QRectF sr(rect.topLeft() * ratio, rect.size() * ratio);
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/* When OpenGL is used, big images are rendered incredibly slow or not at
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all using the QPainter::drawImage() function with a source rect set. So
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we have to tile the image ourself before it can be drawn. */
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if (flags & Map::OpenGL && _img.sizeInBytes() > OPENGL_SIZE_LIMIT) {
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for (int i = sr.left()/TILE_SIZE; i <= sr.right()/TILE_SIZE; i++) {
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for (int j = sr.top()/TILE_SIZE; j <= sr.bottom()/TILE_SIZE; j++) {
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QPoint tl(i * TILE_SIZE, j * TILE_SIZE);
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QRect tile(tl, QSize(TILE_SIZE, TILE_SIZE));
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QImage img(_img.copy(tile));
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img.setDevicePixelRatio(ratio);
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painter->drawImage(tl/ratio, img);
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}
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}
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} else
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painter->drawImage(rect.topLeft(), _img, sr);
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}
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void Image::setDevicePixelRatio(qreal ratio)
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{
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_img.setDevicePixelRatio(ratio);
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}
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