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mirror of https://github.com/tumic0/GPXSee.git synced 2024-11-27 21:24:47 +01:00

Improved bitmap lines drawing

This commit is contained in:
Martin Tůma 2024-02-07 22:10:40 +01:00
parent 96b602bf14
commit 4e7c6e39aa

View File

@ -4,11 +4,10 @@
#include "bitmapline.h"
static QImage img2line(const QImage &img, int width)
static QImage img2line(const QImage &img, int width, int offset)
{
Q_ASSERT(img.format() == QImage::Format_ARGB32_Premultiplied);
QImage res(width * img.devicePixelRatio(), img.height(),
QImage::Format_ARGB32_Premultiplied);
QImage res(width, img.height(), QImage::Format_ARGB32_Premultiplied);
const int srcBpl = img.bytesPerLine();
const int dstBpl = res.bytesPerLine();
const uchar *srcBits = img.bits();
@ -17,8 +16,14 @@ static QImage img2line(const QImage &img, int width)
for (int i = 0; i < img.height(); i++) {
const uchar *srcLine = srcBits + srcBpl * i;
uchar *dstLine = dstBits + dstBpl * i;
int size = 0;
for (int j = dstBpl; j > 0; j -= srcBpl, dstLine += srcBpl)
if (offset) {
size = qMin(dstBpl, srcBpl - 4 * offset);
memcpy(dstLine, srcLine + 4 * offset, size);
dstLine += size;
}
for (int j = dstBpl - size; j > 0; j -= srcBpl, dstLine += srcBpl)
memcpy(dstLine, srcLine, qMin(j, srcBpl));
}
@ -30,16 +35,20 @@ static QImage img2line(const QImage &img, int width)
void BitmapLine::draw(QPainter *painter, const QPolygonF &line,
const QImage &img)
{
int offset = 0;
for (int i = 1; i < line.size(); i++) {
QLineF segment(line.at(i-1).x(), line.at(i-1).y(), line.at(i).x(),
line.at(i).y());
int len = qCeil(segment.length() * img.devicePixelRatio());
painter->save();
painter->translate(segment.p1());
painter->rotate(-segment.angle());
painter->drawImage(0.0, -img.height()/2.0, img2line(img,
qCeil(segment.length())));
painter->drawImage(0.0, -img.height()/2.0, img2line(img, len, offset));
painter->restore();
offset = (len + offset) % img.width();
}
}