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42 lines
1.3 KiB
C++
42 lines
1.3 KiB
C++
#include <QPainter>
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#include "image.h"
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#define TILE_SIZE 256
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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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We have to use a list of dynamically allocated pixmaps as QPainter
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rendering is broken in yet another way with OpenGL and drawPixmap() does
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access already deleted image instances when reusing a single pixmap. */
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if (flags & Map::OpenGL) {
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QList<QPixmap *> list;
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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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QPixmap *pm = new QPixmap(QPixmap::fromImage(_img.copy(tile)));
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list.append(pm);
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pm->setDevicePixelRatio(ratio);
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painter->drawPixmap(tl/ratio, *pm);
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}
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}
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qDeleteAll(list);
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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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