本文整理汇总了C++中mapnik::query::scale_denominator方法的典型用法代码示例。如果您正苦于以下问题：C++ query::scale_denominator方法的具体用法？C++ query::scale_denominator怎么用？C++ query::scale_denominator使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类mapnik::query的用法示例。
在下文中一共展示了query::scale_denominator方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: features
mapnik::featureset_ptr rasterizer_datasource::features(const mapnik::query& q) const
{
std::clog << "Rasterizer::features"
<< ", resolution_type=(" << q.resolution().head << "," << q.resolution().tail.head << ")"
<< ", scale_denominator=" << q.scale_denominator()
<< ", bbox=[" << q.get_bbox().minx() << "," << q.get_bbox().miny() << "," << q.get_bbox().maxx() << "," << q.get_bbox().maxy() << "]"
<< std::endl;
double resx=q.resolution().head,
resy=q.resolution().tail.head,
bbox_width=q.get_bbox().width(),
bbox_height=q.get_bbox().height();
int pixel_width=round(bbox_width * resx),
pixel_height=round(bbox_height * resy);
if (pixel_width<=0 || pixel_height<=0) {
std::clog << "Illegal rasterizer display metrics" << std::endl;
return mapnik::featureset_ptr();
}
std::clog << "Rasterizer generating image of size (" << pixel_width << "," << pixel_height << ")" << std::endl;
// Setup for render
mapnik::feature_ptr feature(mapnik::feature_factory::create(1));
mapnik::image_data_32 image(pixel_width, pixel_height);
rasterize_params params(q, image);
rasterize(params);
// Prepare and return the raster feature
feature->set_raster(boost::make_shared<mapnik::raster>(q.get_bbox(), image));
return boost::make_shared<singleton_featureset>(singleton_featureset(feature));
}