Narrative rendering machinery

1 files changed, 266 insertions, 0 deletions

diff --git a/libstorycode/narrative_render_cairo.c b/libstorycode/narrative_render_cairo.c
new file mode 100644
index 0000000..746ce62
--- /dev/null
+++ b/libstorycode/narrative_render_cairo.c
@@ -0,0 +1,266 @@
+/*
+ * narrative_render_cairo.c
+ *
+ * Copyright © 2013-2019 Thomas White <taw@bitwiz.org.uk>
+ *
+ * This file is part of Colloquium.
+ *
+ * Colloquium is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <cairo.h>
+#include <cairo-pdf.h>
+#include <pango/pangocairo.h>
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "slide.h"
+#include "narrative.h"
+#include "stylesheet.h"
+
+#include "narrative_priv.h"
+
+
+static double lcalc(struct length l, double pd)
+{
+	if ( l.unit == LENGTH_UNIT ) {
+		return l.len;
+	} else {
+		return l.len * pd;
+	}
+}
+
+
+static PangoAlignment to_pangoalignment(enum alignment align)
+{
+	switch ( align ) {
+		case ALIGN_LEFT : return PANGO_ALIGN_LEFT;
+		case ALIGN_RIGHT : return PANGO_ALIGN_RIGHT;
+		case ALIGN_CENTER : return PANGO_ALIGN_CENTER;
+		default: return PANGO_ALIGN_LEFT;
+	}
+}
+
+
+static double wrap_text(struct narrative_item *item, PangoContext *pc,
+                        Stylesheet *ss, enum style_element el, double wrap_w,
+                        PangoFontDescription *fontdesc, enum alignment align)
+{
+	int i;
+	PangoAlignment palignment;
+	double total_h = 0.0;
+
+	if ( item->layouts == NULL ) {
+		item->layouts = malloc(item->n_paras*sizeof(PangoLayout *));
+		if ( item->layouts == NULL ) return 0.0;
+		for ( i=0; i<item->n_paras; i++ ) {
+			item->layouts[i] = NULL;
+		}
+	}
+
+	if ( item->align == ALIGN_INHERIT ) {
+		/* Use value from stylesheet */
+		palignment = to_pangoalignment(align);
+	} else {
+		/* Use item-specific value */
+		palignment = to_pangoalignment(item->align);
+	}
+
+	for ( i=0; i<item->n_paras; i++ ) {
+
+		PangoRectangle rect;
+
+		if ( item->layouts[i] == NULL ) {
+			item->layouts[i] = pango_layout_new(pc);
+		}
+		pango_layout_set_width(item->layouts[i], pango_units_from_double(wrap_w));
+		pango_layout_set_text(item->layouts[i], item->paragraphs[i], -1);
+		pango_layout_set_alignment(item->layouts[i], palignment);
+		pango_layout_set_font_description(item->layouts[i], fontdesc);
+
+		/* FIXME: Handle *bold*, _underline_, /italic/ etc. */
+		//pango_layout_set_attributes(item->layouts[i], attrs);
+		//pango_attr_list_unref(attrs);
+
+		pango_layout_get_extents(item->layouts[i], NULL, &rect);
+		total_h += pango_units_to_double(rect.height);
+
+	}
+
+	return total_h;
+}
+
+
+static void draw_text(struct narrative_item *item, cairo_t *cr)
+{
+	int i;
+	double hpos = 0.0;
+
+	cairo_save(cr);
+
+	for ( i=0; i<item->n_paras; i++ ) {
+
+		PangoRectangle rect;
+		double cur_h;
+
+		pango_layout_get_extents(item->layouts[i], NULL, &rect);
+		cur_h = rect.height;
+
+		cairo_save(cr);
+		cairo_translate(cr, 0.0, hpos);
+
+		//if ( (hpos + cur_h > min_y) && (hpos < max_y) ) {
+			cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
+			pango_cairo_update_layout(cr, item->layouts[i]);
+			pango_cairo_show_layout(cr, item->layouts[i]);
+			cairo_fill(cr);
+		//} /* else paragraph is not visible */
+
+		hpos += cur_h;
+		cairo_restore(cr);
+
+	}
+
+	cairo_restore(cr);
+}
+
+
+int narrative_wrap(Narrative *n, Stylesheet *stylesheet, PangoLanguage *lang,
+                   PangoContext *pc, double w)
+{
+	int i;
+	struct length pad[4];
+	double pad_l, pad_r, pad_t, pad_b;
+	const char *font;
+	PangoFontDescription *fontdesc;
+	double wrap_w;
+	enum alignment align;
+
+	if ( stylesheet_get_padding(stylesheet, STYEL_NARRATIVE, pad) ) return 1;
+	pad_l = lcalc(pad[0], w);
+	pad_r = lcalc(pad[1], w);
+	pad_t = lcalc(pad[2], 1024.0);  /* dummy value, h not allowed in narrative */
+	pad_b = lcalc(pad[3], 1024.0);  /* dummy value, h not allowed in narrative */
+	wrap_w = w - pad_l - pad_r;
+
+	n->w = w;
+	n->total_h = pad_t + pad_b;
+
+	font = stylesheet_get_font(stylesheet, STYEL_NARRATIVE, NULL, &align);
+	if ( font == NULL ) return 1;
+	fontdesc = pango_font_description_from_string(font);
+
+	for ( i=0; i<n->n_items; i++ ) {
+
+		switch ( n->items[i].type ) {
+
+			case NARRATIVE_ITEM_TEXT :
+			n->total_h += wrap_text(&n->items[i], pc, stylesheet,
+			                        STYEL_NARRATIVE, wrap_w, fontdesc,
+			                        align);
+			break;
+
+			case NARRATIVE_ITEM_BP :
+			n->total_h += wrap_text(&n->items[i], pc, stylesheet,
+			                        STYEL_NARRATIVE, wrap_w, fontdesc,
+			                        align);
+			break;
+
+			case NARRATIVE_ITEM_SLIDE :
+			break;
+
+			default :
+			break;
+
+		}
+	}
+
+	return 0;
+}
+
+
+double narrative_get_height(Narrative *n)
+{
+	return n->total_h;
+}
+
+
+int narrative_render_cairo(Narrative *n, cairo_t *cr, Stylesheet *stylesheet,
+                           PangoLanguage *lang, PangoContext *pc, double w)
+{
+	int i, r;
+	enum gradient bg;
+	double bgcol[4];
+	double bgcol2[4];
+	cairo_pattern_t *patt = NULL;
+
+	r = stylesheet_get_background(stylesheet, STYEL_SLIDE, &bg, bgcol, bgcol2);
+	if ( r ) return 1;
+
+	/* Overall background */
+	cairo_rectangle(cr, 0.0, 0.0, n->w, n->total_h);
+	switch ( bg ) {
+
+		case GRAD_NONE:
+		cairo_set_source_rgb(cr, bgcol[0], bgcol[1], bgcol[2]);
+		break;
+
+		case GRAD_VERT:
+		patt = cairo_pattern_create_linear(0.0, 0.0, 0.0, n->total_h);
+		cairo_pattern_add_color_stop_rgb(patt, 0.0, bgcol[0], bgcol[1], bgcol[2]);
+		cairo_pattern_add_color_stop_rgb(patt, 1.0, bgcol2[0], bgcol2[1], bgcol2[2]);
+		cairo_set_source(cr, patt);
+		break;
+
+		case GRAD_HORIZ:
+		patt = cairo_pattern_create_linear(0.0, 0.0, n->w, 0.0);
+		cairo_pattern_add_color_stop_rgb(patt, 0.0, bgcol[0], bgcol[1], bgcol[2]);
+		cairo_pattern_add_color_stop_rgb(patt, 1.0, bgcol2[0], bgcol2[1], bgcol2[2]);
+		cairo_set_source(cr, patt);
+		break;
+
+	}
+	cairo_fill(cr);
+
+	for ( i=0; i<n->n_items; i++ ) {
+
+		switch ( n->items[i].type ) {
+
+			case NARRATIVE_ITEM_TEXT :
+			draw_text(&n->items[i], cr);
+			break;
+
+			case NARRATIVE_ITEM_BP :
+			draw_text(&n->items[i], cr);
+			break;
+
+			case NARRATIVE_ITEM_SLIDE :
+			break;
+
+			default :
+			break;
+
+		}
+	}
+
+	return 0;
+}