Put together a simple text renderer to a PNG

3 files changed, 71 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..11c8a1e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.o
+text
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b27a35c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,10 @@
+CFLAGS += -Wall -Wextra -Wpedantic
+CFLAGS += `pkg-config --cflags cairo pango pangocairo`
+LDLIBS += -lm `pkg-config --libs cairo pango pangocairo`
+
+all: text
+
+clean:
+	rm -f text *.o
+
+.PHONY: all clean
diff --git a/text.c b/text.c
new file mode 100644
index 0000000..1e488a5
--- /dev/null
+++ b/text.c
@@ -0,0 +1,59 @@
+#include <math.h>
+#include <stdio.h>
+
+#include <cairo.h>
+#include <glib-object.h>
+#include <pango/pango.h>
+#include <pango/pangocairo.h>
+
+void draw_text(cairo_t *, const char *);
+
+static const int MARGIN = 20;
+static const int WIDTH = 800;
+static const int HEIGHT = 1131;
+static const char * FONT = "Serif 34";
+
+
+int main(int argc, const char ** argv)
+{
+	if (1 >= argc)
+	{
+		dprintf(2, "Usage: %s OUTPUT [TEXT]\n", argv[0]);
+		return 1;
+	}
+	const char * filename = argv[1];
+	const char * text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
+	if (3 == argc)
+		text = argv[2];
+	cairo_surface_t * surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, WIDTH, HEIGHT);
+	cairo_t * ctx = cairo_create(surface);
+	cairo_scale(ctx, 1, 1);
+	cairo_set_source_rgb(ctx, 1., 1., 1.);
+	cairo_paint(ctx);
+	cairo_set_source_rgb(ctx, 0., 0., 0.);
+	draw_text(ctx, text);
+	cairo_destroy(ctx);
+	cairo_status_t status = cairo_surface_write_to_png(surface, filename);
+	cairo_surface_destroy(surface);
+	if (CAIRO_STATUS_SUCCESS != status)
+	{
+		dprintf(2, "Could not save output to %s\n", filename);
+		return 1;
+	}
+}
+
+
+void draw_text(cairo_t * ctx, const char * text)
+{
+	cairo_translate(ctx, MARGIN, MARGIN);
+	PangoLayout * layout = pango_cairo_create_layout(ctx);
+	PangoFontDescription * desc = pango_font_description_from_string(FONT);
+	pango_layout_set_font_description(layout, desc);
+	pango_font_description_free(desc);
+	pango_layout_set_text(layout, text, -1);
+	pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
+	pango_layout_set_width(layout, (WIDTH - 2 * MARGIN) * PANGO_SCALE);
+	pango_cairo_update_layout(ctx, layout);
+	pango_cairo_show_layout(ctx, layout);
+	g_object_unref(layout);
+}