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read only the portion of the raster from file that is clipped to view window

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git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@327 c8812cc2-4d05-0410-92ff-de0c093fc19c
This commit is contained in:
stevehalasz 2003-12-17 16:06:03 +00:00
parent 8b8b20a566
commit 5a3f36e6ce
4 changed files with 83 additions and 40 deletions
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98
src/qgsrasterlayer.cpp
View File

@ -23,18 +23,16 @@
#include "qgsrect.h"
#include "qgsrasterlayer.h"
#include "gdal_priv.h"
//#include "qtiffio.h"
QgsRasterLayer::QgsRasterLayer(QString path, QString baseName)
:QgsMapLayer(RASTER, baseName, path)
{
std::cout << "QgsRasterLayer::QgsRasterLayer()" << std::endl;
//std::cout << "QgsRasterLayer::QgsRasterLayer()" << std::endl;
GDALAllRegister();
gdalDataset = (GDALDataset *) GDALOpen( path, GA_ReadOnly );
std::cout << "Raster Count: " << gdalDataset->GetRasterCount() << std::endl;
//std::cout << "Raster Count: " << gdalDataset->GetRasterCount() << std::endl;
double adfGeoTransform[6];
if( gdalDataset->GetGeoTransform( adfGeoTransform ) == CE_None )
{
printf( "Origin = (%.6f,%.6f)\n",
@ -44,8 +42,6 @@ QgsRasterLayer::QgsRasterLayer(QString path, QString baseName)
adfGeoTransform[1], adfGeoTransform[5] );
}
const char *projRef = gdalDataset->GetProjectionRef();
double XMax = adfGeoTransform[0] + gdalDataset->GetRasterXSize() * adfGeoTransform[1] +
gdalDataset->GetRasterYSize() * adfGeoTransform[2];
double YMin = adfGeoTransform[3] + gdalDataset->GetRasterXSize() * adfGeoTransform[4] +
@ -64,34 +60,51 @@ QgsRasterLayer::~QgsRasterLayer()
void QgsRasterLayer::draw(QPainter * p, QgsRect * viewExtent, QgsCoordinateTransform * cXf)
{
/*
// init the tiff handler
//qInitTiffIO();
//std::cout << "Image source is " << source() << std::endl;
//QImage *image = new QImage(source());
//if(!image){
// qWarning("Failed to load the image using path stored in source()");
//}else{
// qWarning("Loaded image");
//}
//
//qWarning("Attempting to draw the image");
//p->drawImage(0, 0, *image);
//delete image;
*/
std::cout << "QgsRasterLayer::draw()" << std::endl;
std::cout << "gdalDataset->GetRasterCount(): " << gdalDataset->GetRasterCount() << std::endl;
//std::cout << "QgsRasterLayer::draw()" << std::endl;
//std::cout << "gdalDataset->GetRasterCount(): " << gdalDataset->GetRasterCount() << std::endl;
std::cout << "Layer extent: " << layerExtent.stringRep() << std::endl;
// get dimensions of raster image in map coordinate space
QgsPoint topLeft = cXf->transform(layerExtent.xMin(), layerExtent.yMax());
QgsPoint bottomRight = cXf->transform(layerExtent.xMax(), layerExtent.yMin());
//QPoint topLeft = cXf->transform(topLeft);
//QPoint bottomRight = layerExtent.bottomRight();
//bottomRight = cXf->transform(bottomRight);
// clip raster extent to view extent
QgsRect rasterExtent = viewExtent->intersect(&layerExtent);
std::cout << "viewXMin: " << viewExtent->xMin() <<std::endl;
std::cout << "viewYMax: " << viewExtent->yMax() <<std::endl;
std::cout << "viewXMax: " << viewExtent->xMax() <<std::endl;
std::cout << "viewYMin: " << viewExtent->yMin() <<std::endl;
std::cout << "rasterXMin: " << rasterExtent.xMin() <<std::endl;
std::cout << "rasterYMax: " << rasterExtent.yMax() <<std::endl;
std::cout << "rasterXMax: " << rasterExtent.xMax() <<std::endl;
std::cout << "rasterYMin: " << rasterExtent.yMin() <<std::endl;
if (rasterExtent.isEmpty()) {
// nothing to do
return;
}
// calculate raster pixel offsets from origin to clipped rect
// we're only interested in positive offsets where the origin of the raster
// is northwest of the origin of the view
int rXOff = static_cast<int>((viewExtent->xMin() - layerExtent.xMin()) / fabs(adfGeoTransform[1]));
rXOff = rXOff >? 0;
int rYOff = static_cast<int>((layerExtent.yMax() - viewExtent->yMax()) / fabs(adfGeoTransform[5]));
rYOff = rYOff >? 0;
std::cout << "rXOff: " << rXOff <<std::endl;
std::cout << "rYOff: " << rYOff <<std::endl;
// get dimensions of clipped raster image in raster pixel space
double rXmin = (rasterExtent.xMin() - adfGeoTransform[0]) / adfGeoTransform[1];
double rXmax = (rasterExtent.xMax() - adfGeoTransform[0]) / adfGeoTransform[1];
double rYmin = (rasterExtent.yMin() - adfGeoTransform[3]) / adfGeoTransform[5];
double rYmax = (rasterExtent.yMax() - adfGeoTransform[3]) / adfGeoTransform[5];
int rXSize = abs(static_cast<int>(rXmax - rXmin));
int rYSize = abs(static_cast<int>(rYmax - rYmin));
// get dimensions of clipped raster image in device coordinate space
QgsPoint topLeft = cXf->transform(rasterExtent.xMin(), rasterExtent.yMax());
QgsPoint bottomRight = cXf->transform(rasterExtent.xMax(), rasterExtent.yMin());
int lXSize = bottomRight.xToInt() - topLeft.xToInt();
int lYSize = bottomRight.yToInt() - topLeft.yToInt();
std::cout << "xMin: " << layerExtent.xMin() <<std::endl;
std::cout << "yMax: " << layerExtent.yMax() <<std::endl;
std::cout << "xMax: " << layerExtent.xMax() <<std::endl;
@ -108,26 +121,31 @@ void QgsRasterLayer::draw(QPainter * p, QgsRect * viewExtent, QgsCoordinateTrans
for (int i = 1; i <= gdalDataset->GetRasterCount(); i++) {
GDALRasterBand *gdalBand = gdalDataset->GetRasterBand( i );
std::cout << "gdalBand->GetOverviewCount(): " << gdalBand->GetOverviewCount() <<std::endl;
//std::cout << "gdalBand->GetOverviewCount(): " << gdalBand->GetOverviewCount() <<std::endl;
int nXSize = gdalBand->GetXSize();
int nYSize = gdalBand->GetYSize();
// read entire raster
//int nXSize = gdalBand->GetXSize() - nXOff;
//int nYSize = gdalBand->GetYSize() - nYOff;
// make sure we don't exceed size of raster
rXSize = rXSize <? gdalBand->GetXSize();
rYSize = rYSize <? gdalBand->GetYSize();
std::cout << "rXSize: " << rXSize <<std::endl;
std::cout << "rYSize: " << rYSize <<std::endl;
// read entire clipped area of raster
// treat scandata as a pseudo-multidimensional array
// RasterIO() takes care of scaling down image
// TODO: need to clip to map size or we run out of memory when zooming in
uint *scandata = (uint*) CPLMalloc(sizeof(uint)*lXSize * sizeof(uint)*lYSize);
CPLErr result = gdalBand->RasterIO(
GF_Read, 0, 0, nXSize, nYSize, scandata, lXSize, lYSize, GDT_UInt32, 0, 0 );
GF_Read, rXOff, rYOff, rXSize, rYSize, scandata, lXSize, lYSize, GDT_UInt32, 0, 0 );
GDALColorTable *colorTable = gdalBand->GetColorTable();
// print each point in scandata using color looked up in color table
for (int i = 0; i < lXSize; i++) {
for (int j =0; j < lYSize; j++) {
const GDALColorEntry *colorEntry = GDALGetColorEntry(colorTable, scandata[i*lXSize + j]);
for (int y = 0; y < lYSize; y++) {
for (int x =0; x < lXSize; x++) {
const GDALColorEntry *colorEntry = GDALGetColorEntry(colorTable, scandata[y*lXSize + x]);
p->setPen(QColor(colorEntry->c1, colorEntry->c2, colorEntry->c3));
p->drawPoint(topLeft.xToInt() + j, topLeft.yToInt() + i);
p->drawPoint(topLeft.xToInt() + x, topLeft.yToInt() + y);
}
}

2
src/qgsrasterlayer.h
View File

@ -38,6 +38,8 @@ public:
private:
GDALDataset *gdalDataset;
// values for mapping pixel to world coordinates
double adfGeoTransform[6];
signals:
void repaintRequested();

19
src/qgsrect.cpp
View File

@ -136,6 +136,25 @@ void QgsRect::expand(double scaleFactor, QgsPoint *cp)
ymax = centerY + newHeight;
}
QgsRect QgsRect::intersect(QgsRect *rect)
{
QgsRect intersection = QgsRect();
intersection.setXmin( xmin >? rect->xMin() );
intersection.setYmin( ymin >? rect->yMin() );
intersection.setXmax( xmax <? rect->xMax() );
intersection.setYmax( ymax <? rect->yMax() );
return intersection;
}
bool QgsRect::isEmpty()
{
if (xmax <= xmin || ymax <= ymin) {
return TRUE;
} else {
return FALSE;
}
}
QString QgsRect::stringRep() const
{
QString tmp;

4
src/qgsrect.h
View File

@ -63,6 +63,10 @@ class QgsRect{
void scale(double, QgsPoint *c =0);
//! Expand the rectangle to support zoom out scaling
void expand(double, QgsPoint *c = 0);
//! return the intersection with the given rectangle
QgsRect intersect(QgsRect *rect);
//! test if rectangle is empty
bool isEmpty();
//! returns string representation of form xmin,ymin xmax,ymax
QString stringRep() const;
/*! Comparison operator