libui/unix/drawtext.c

82 lines
2.6 KiB
C

// 11 march 2018
#include "uipriv_unix.h"
#include "draw.h"
#include "attrstr.h"
struct uiDrawTextLayout {
PangoLayout *layout;
};
// we need a context for a few things
// the documentation suggests creating cairo_t-specific, GdkScreen-specific, or even GtkWidget-specific contexts, but we can't really do that because we want our uiDrawTextFonts and uiDrawTextLayouts to be context-independent
// we could use pango_font_map_create_context(pango_cairo_font_map_get_default()) but that will ignore GDK-specific settings
// so let's use gdk_pango_context_get() instead; even though it's for the default screen only, it's good enough for us
#define mkGenericPangoCairoContext() (gdk_pango_context_get())
static const PangoAlignment pangoAligns[] = {
[uiDrawTextAlignLeft] = PANGO_ALIGN_LEFT,
[uiDrawTextAlignCenter] = PANGO_ALIGN_CENTER,
[uiDrawTextAlignRight] = PANGO_ALIGN_RIGHT,
};
uiDrawTextLayout *uiDrawNewTextLayout(uiDrawTextLayoutParams *p)
{
uiDrawTextLayout *tl;
PangoContext *context;
PangoFontDescription *desc;
PangoAttrList *attrs;
int pangoWidth;
tl = uiprivNew(uiDrawTextLayout);
// in this case, the context is necessary to create the layout
// the layout takes a ref on the context so we can unref it afterward
context = mkGenericPangoCairoContext();
tl->layout = pango_layout_new(context);
g_object_unref(context);
// this is safe; pango_layout_set_text() copies the string
pango_layout_set_text(tl->layout, uiAttributedStringString(p->String), -1);
desc = uiprivFontDescriptorToPangoFontDescription(p->DefaultFont);
pango_layout_set_font_description(tl->layout, desc);
// this is safe; the description is copied
pango_font_description_free(desc);
pangoWidth = cairoToPango(p->Width);
if (p->Width < 0)
pangoWidth = -1;
pango_layout_set_width(tl->layout, pangoWidth);
pango_layout_set_alignment(tl->layout, pangoAligns[p->Align]);
attrs = uiprivAttributedStringToPangoAttrList(p);
pango_layout_set_attributes(tl->layout, attrs);
pango_attr_list_unref(attrs);
return tl;
}
void uiDrawFreeTextLayout(uiDrawTextLayout *tl)
{
g_object_unref(tl->layout);
uiprivFree(tl);
}
void uiDrawText(uiDrawContext *c, uiDrawTextLayout *tl, double x, double y)
{
// TODO have an implicit save/restore on each drawing functions instead? and is this correct?
cairo_set_source_rgb(c->cr, 0.0, 0.0, 0.0);
cairo_move_to(c->cr, x, y);
pango_cairo_show_layout(c->cr, tl->layout);
}
void uiDrawTextLayoutExtents(uiDrawTextLayout *tl, double *width, double *height)
{
PangoRectangle logical;
pango_layout_get_extents(tl->layout, NULL, &logical);
*width = pangoToCairo(logical.width);
*height = pangoToCairo(logical.height);
}