Image DPI are 0/0
New DPI values will be 1200/1200
Saved .png image DPI are 1200/1200
Saved .jpg image DPI are 1200/1200
Saved .tif image DPI are 1200/1200
Saved .bmp image DPI are 1200/1200
Saved .gif image DPI are 72/72
Done

#include <Core/Core.h>
#include <plugin/png/png.h>
#include <plugin/jpg/jpg.h>
#include <plugin/tif/tif.h>
#include <plugin/bmp/bmp.h>
#include <plugin/gif/gif.h>

using namespace Upp;

void PrintDPI(String fileName, String format) {
	Image img = StreamRaster::LoadFileAny(fileName + format);
	Size dpi = img.GetDPI();
	puts(Format("Saved " + format + " image DPI are %d/%d", dpi.cx, dpi.cy));	
}

CONSOLE_APP_MAIN
{
	Image img = StreamRaster::LoadFileAny(AppendFileName(GetDesktopFolder(), "demo.png"));
	if (!img) 
		puts("No image");
	else {
		ImageBuffer image(img);
		
		Size dpi = image.GetDPI();
		puts(Format("Image DPI are %d/%d", dpi.cx, dpi.cy));
		image.SetDPI(Size(1200, 1200));
		puts("New DPI values will be 1200/1200");
		
		img = image;
		String fileName = AppendFileName(GetDesktopFolder(), "demo2");
		
		PNGEncoder png;
		png.SaveFile(fileName + ".png", img);	
		PrintDPI(fileName, ".png");
		
		JPGEncoder jpeg;
		jpeg.SaveFile(fileName + ".jpg", img);	
		PrintDPI(fileName, ".jpg");
		
		TIFEncoder tiff;
		tiff.SaveFile(fileName + ".tif", img);	
		PrintDPI(fileName, ".tif");

		BMPEncoder bmp;
		bmp.SaveFile(fileName + ".bmp", img);			
		PrintDPI(fileName, ".bmp");
				
		GIFEncoder gif;
		gif.SaveFile(fileName + ".gif", img);			
		PrintDPI(fileName, ".gif");
		
		puts("Done");
	}
	getchar();
}