src/map/bitmapline.cpp

   1 #include <QPainter>
   2 #include <QImage>
   3 #include <QtMath>
   4 #include "bitmapline.h"
   5
   6
   7 static QImage img2line(const QImage &img, int width, int offset)
   8 {
   9         Q_ASSERT(img.format() == QImage::Format_ARGB32_Premultiplied);
  10         QImage res(width, img.height(), QImage::Format_ARGB32_Premultiplied);
  11         const int srcBpl = img.bytesPerLine();
  12         const int dstBpl = res.bytesPerLine();
  13         const uchar *srcBits = img.bits();
  14         uchar *dstBits = res.bits();
  15
  16         for (int i = 0; i < img.height(); i++) {
  17                 const uchar *srcLine = srcBits + srcBpl * i;
  18                 uchar *dstLine = dstBits + dstBpl * i;
  19                 int size = 0;
  20
  21                 if (offset) {
  22                         size = qMin(dstBpl, srcBpl - 4 * offset);
  23                         memcpy(dstLine, srcLine + 4 * offset, size);
  24                         dstLine += size;
  25                 }
  26                 for (int j = dstBpl - size; j > 0; j -= srcBpl, dstLine += srcBpl)
  27                         memcpy(dstLine, srcLine, qMin(j, srcBpl));
  28         }
  29
  30         res.setDevicePixelRatio(img.devicePixelRatio());
  31
  32         return res;
  33 }
  34
  35 void BitmapLine::draw(QPainter *painter, const QPolygonF &line,
  36   const QImage &img)
  37 {
  38         int offset = 0;
  39
  40         for (int i = 1; i < line.size(); i++) {
  41                 QLineF segment(line.at(i-1).x(), line.at(i-1).y(), line.at(i).x(),
  42                   line.at(i).y());
  43                 int len = qCeil(segment.length() * img.devicePixelRatio());
  44
  45                 painter->save();
  46                 painter->translate(segment.p1());
  47                 painter->rotate(-segment.angle());
  48                 painter->drawImage(0.0, -img.height()/2.0, img2line(img, len, offset));
  49                 painter->restore();
  50
  51                 offset = (len + offset) % img.width();
  52         }
  53 }
  54
  55 void BitmapLine::draw(QPainter *painter, const QVector<QPolygonF> &lines,
  56   const QImage &img)
  57 {
  58         for (int i = 0; i < lines.size(); i++)
  59                 draw(painter, lines.at(i), img);
  60 }