KmzGroundOverlayExport: New feature

Add export of KML/KMZ ground overlay files, based on MapPrinter's page
drawing and GDAL's vsizip virtual file system. Other than our existing
output variant (raster, PDF, printing), KML needs raster images
oriented to true north.
Formally, this is a "KML" export, with "KMZ" being a zipped variant.
Following populer recognition and usage, we prefer labelling as "KMZ".
Resolves GH-138 (KMZ export).

Author: dg0yt

src/core/map_printer.cpp

@@ -391,6 +391,12 @@ const QPrinterInfo* MapPrinter::imageTarget()
 	return &image_target;
 }
 
+const QPrinterInfo* MapPrinter::kmzTarget()
+{
+	static QPrinterInfo kmz_target; // TODO: set name and features?
+	return &kmz_target;
+}
+
 
 // QPageSize (::key(), ::name()) made this list mostly obsolete.
 // But we keep it in v0.9 for loading maps where we used names
@@ -454,14 +460,17 @@ void MapPrinter::setTarget(const QPrinterInfo* new_target)
 			target = new_target;
 		else if (new_target == imageTarget())
 			target = new_target;
+		else if (new_target == kmzTarget())
+			target = new_target;
 		else
 		{
 			// We don't own this target, so we need to make a copy.
 			target_copy = *new_target;
 			target = &target_copy;
 		}
 
-		if (old_target == imageTarget() || new_target == imageTarget())
+		if (old_target == imageTarget() || new_target == imageTarget()
+		    || old_target == kmzTarget() || new_target == kmzTarget())
 		{
 			// No page margins. Will emit pageFormatChanged( ).
 			setCustomPageSize(page_format.page_rect.size());
@@ -536,7 +545,8 @@ bool MapPrinter::isPrinter() const
 {
 	bool is_printer = target
 	                  && target != imageTarget()
-	                  && target != pdfTarget();
+	                  && target != pdfTarget()
+	                  && target != kmzTarget();
 	return is_printer;
 }
 
@@ -547,7 +557,7 @@ void MapPrinter::setPrintArea(const QRectF& area)
 	{
 		print_area = area;
 
-		if (target == imageTarget() && print_area.size() != page_format.paper_dimensions)
+		if ((target == imageTarget() || target == kmzTarget()) && print_area.size() != page_format.paper_dimensions)
 			setCustomPageSize(print_area.size() * scale_adjustment);
 
 		updatePageBreaks();
@@ -627,7 +637,7 @@ void MapPrinter::setOverlap(qreal h_overlap, qreal v_overlap)
 
 void MapPrinter::updatePaperDimensions()
 {
-	if (target == imageTarget() && page_format.page_size == QPageSize::Custom)
+	if ((target == imageTarget() || target == kmzTarget()) && page_format.page_size == QPageSize::Custom)
 	{
 		// No margins, no need to query QPrinter.
 		page_format.page_rect = QRectF(QPointF(0.0, 0.0), page_format.paper_dimensions);
@@ -639,7 +649,7 @@ void MapPrinter::updatePaperDimensions()
 
 	QPrinter* printer = target ? new QPrinter(*target, QPrinter::HighResolution)
 	                           : new QPrinter(QPrinter::HighResolution);
-	if (!printer->isValid() || target == imageTarget() || target == pdfTarget())
+	if (!printer->isValid() || target == imageTarget() || target == kmzTarget() || target == pdfTarget())
 		printer->setOutputFormat(QPrinter::PdfFormat);
 
 	if (page_format.page_size == QPageSize::Custom)
@@ -657,7 +667,7 @@ void MapPrinter::updatePaperDimensions()
 	page_format.page_rect = printer->paperRect(QPrinter::Millimeter);
 	page_format.paper_dimensions = page_format.page_rect.size();
 
-	if ( target != imageTarget() && target != pdfTarget() &&
+	if ( target != imageTarget() && target != kmzTarget() && target != pdfTarget() &&
 		 page_format.page_size != QPageSize::Custom )
 	{
 		page_format.page_rect = printer->pageRect(QPrinter::Millimeter);
@@ -896,7 +906,7 @@ void MapPrinter::takePrinterSettings(const QPrinter* printer)
 	if (!printer) return;
 
 	MapPrinterPageFormat f(*printer);
-	if (target == pdfTarget() || target == imageTarget())
+	if (target == pdfTarget() || target == imageTarget() || target == kmzTarget())
 	{
 		f.page_rect = QRectF(QPointF(0.0, 0.0), f.paper_dimensions);
 	}
@@ -966,7 +976,7 @@ void MapPrinter::drawPage(QPainter* device_painter, const QRectF& page_extent, c
 	 * When the target is an image, use the temporary image to enforce the given
 	 * resolution.
 	 */
-	const bool use_buffer_for_map = rasterModeSelected() || target == imageTarget() || engineWillRasterize();
+	const bool use_buffer_for_map = rasterModeSelected() || target == imageTarget() || target == kmzTarget() || engineWillRasterize();
 	bool use_page_buffer = use_buffer_for_map;
 
 	auto first_front_template = map.getFirstFrontTemplate();
@@ -1234,7 +1244,7 @@ void MapPrinter::drawSeparationPages(QPrinter* printer, QPainter* device_painter
 
 	// Translate and clip for margins and print area
 	device_painter->translate(-page_extent.left(), -page_extent.top());
-	device_painter->setClipRect(page_extent.intersected(print_area), Qt::ReplaceClip);
+	device_painter->setClipRect(page_extent.intersected(print_area).adjusted(-10, 10, 10, 10), Qt::ReplaceClip);
 
 	bool need_new_page = false;
 	for (int i = map.getNumColors() - 1; i >= 0; --i)

src/core/map_printer.h

@@ -229,6 +229,9 @@ Q_OBJECT
 	/** Returns a QPrinterInfo pointer which signals printing to a raster file. */
 	static const QPrinterInfo* imageTarget();
 
+	/** Returns a QPrinterInfo pointer which signals printing to a KML ground overlay. */
+	static const QPrinterInfo* kmzTarget();
+	
 	/** Returns a reference to a hash which maps paper sizes to names as C strings.
 	 *  These strings are not translated.
 	 *

src/gdal/CMakeLists.txt

@@ -34,6 +34,7 @@ set(MAPPER_GDAL_SOURCES
   gdal_manager.cpp
   gdal_settings_page.cpp
   gdal_template.cpp
+  kmz_groundoverlay_export.cpp
   ogr_file_format.cpp
   ogr_template.cpp
   mapper-osmconf.ini