image-surface.cc

An example of using Cairo::ImageSurface class to render to PNG.

An example of using Cairo::ImageSurface class to render to PNG

/* M_PI is defined in math.h in the case of Microsoft Visual C++, Solaris,
* et. al.
*/
#include <string>
#include <iostream>
#include <cairommconfig.h>
#include <cairomm/context.h>
#include <cairomm/surface.h>
#include <cmath>
int main()
{
auto surface =
Cairo::ImageSurface::create(Cairo::FORMAT_ARGB32, 600, 400);
auto cr = Cairo::Context::create(surface);
cr->save(); // save the state of the context
cr->set_source_rgb(0.86, 0.85, 0.47);
cr->paint(); // fill image with the color
cr->restore(); // color is back to black now
cr->save();
// draw a border around the image
cr->set_line_width(20.0); // make the line wider
cr->rectangle(0.0, 0.0, surface->get_width(), surface->get_height());
cr->stroke();
cr->set_source_rgba(0.0, 0.0, 0.0, 0.7);
// draw a circle in the center of the image
cr->arc(surface->get_width() / 2.0, surface->get_height() / 2.0,
surface->get_height() / 4.0, 0.0, 2.0 * M_PI);
cr->stroke();
// draw a diagonal line
cr->move_to(surface->get_width() / 4.0, surface->get_height() / 4.0);
cr->line_to(surface->get_width() * 3.0 / 4.0, surface->get_height() * 3.0 / 4.0);
cr->stroke();
cr->restore();
#ifdef CAIRO_HAS_PNG_FUNCTIONS
std::string filename = "image.png";
surface->write_to_png(filename);
std::cout << "Wrote png file \"" << filename << "\"" << std::endl;
#else
std::cout << "You must compile cairo with PNG support for this example to work."
<< std::endl;
#endif
}
iostream
string
cmath
std::string
basic_string< char > string
std::endl
basic_ostream< _CharT, _Traits > & endl(basic_ostream< _CharT, _Traits > &__os)
std::cout
ostream cout
Cairo::Context::create
static RefPtr< Context > create(const RefPtr< Surface > &target)
Cairo::ImageSurface::create
static RefPtr< ImageSurface > create(Format format, int width, int height)
Creates an image surface of the specified format and dimensions.
Cairo::FORMAT_ARGB32
@ FORMAT_ARGB32
Each pixel is a 32-bit quantity, with alpha in the upper 8 bits, then red, then green,...
Definition enums.h:347