First Commit

libui-ng/unix/drawtext.c

@@ -0,0 +1,103 @@
+// 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);
+}
+
+void uiLoadControlFont(uiFontDescriptor *f)
+{
+	GtkWidget *widget;
+	GtkStyleContext *style;
+	PangoFontDescription *fontdesc;
+
+	widget = g_object_ref_sink(gtk_label_new(""));
+	style = gtk_widget_get_style_context(widget);
+	gtk_style_context_get(style, GTK_STATE_FLAG_NORMAL,
+		"font", &fontdesc, NULL);
+	uiprivFontDescriptorFromPangoFontDescription(fontdesc, f);
+	// pdesc is transfer-full and thus is a copy
+	pango_font_description_free(fontdesc);
+	g_object_unref(widget);
+}
+
+void uiFreeFontDescriptor(uiFontDescriptor *desc)
+{
+	// TODO ensure this is synchronized with fontmatch.c
+	uiFreeText((char *) (desc->Family));
+}