From 55f10b87696cd22d42d30f41f1099dda1572b584 Mon Sep 17 00:00:00 2001
From: Werner Almesberger <werner@almesberger.net>
Date: Mon, 1 Aug 2016 01:34:27 -0300
Subject: [PATCH] sch2fig/: support multi-page PDF

---
 sch2fig/TODO    |  1 -
 sch2fig/cairo.c | 37 ++++++++++++++++++++++++++++++++++---
 sch2fig/layer.c |  6 ++++++
 sch2fig/layer.h |  1 +
 4 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/sch2fig/TODO b/sch2fig/TODO
index c2d1725..0697dd1 100644
--- a/sch2fig/TODO
+++ b/sch2fig/TODO
@@ -14,7 +14,6 @@
 - PDF TOC
 - let user set PNG size or zoom level
 - implement dashed lines in cairo.c
-- implement multi-page PDF output in cairo.o
 - use correct color for hierarchical items, 0x848400 (or close) instead of
   COLOR_BROWN2
 - directly pick versions out of git, without requiring checkout to file
diff --git a/sch2fig/cairo.c b/sch2fig/cairo.c
index 023cefd..536e357 100644
--- a/sch2fig/cairo.c
+++ b/sch2fig/cairo.c
@@ -11,6 +11,7 @@
  */
 
 
+#include <stddef.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -47,6 +48,9 @@ struct cairo_ctx {
 	cairo_t *cr;
 	cairo_surface_t *s;
 
+	struct layer *sheets;	/* for PDF */
+	unsigned n_sheets;
+
 	const char *output_name;
 };
 
@@ -230,6 +234,9 @@ static struct cairo_ctx *init_common(int argc, char *const *argv)
 	cc->xo = cc->yo = 0;
 	cc->scale = DEFAULT_SCALE;
 
+	cc->sheets = NULL;
+	cc->n_sheets = 0;
+
 	cc->output_name = NULL;
 	while ((c = getopt(argc, argv, "o:s:")) != EOF)
 		switch (c) {
@@ -322,23 +329,46 @@ static void cr_png_end(void *ctx)
 }
 
 
+static void cr_pdf_new_sheet(void *ctx)
+{
+	struct cairo_ctx *cc = ctx;
+
+	cc->n_sheets++;
+	cc->sheets = realloc(cc->sheets, sizeof(struct layer) * cc->n_sheets);
+	if (!cc->sheets) {
+		perror("realloc");
+		exit(1);
+	}
+	cc->sheets[cc->n_sheets - 1] = cc->layer;
+	layer_wipe(&cc->layer);
+}
+
+
 static void cr_pdf_end(void *ctx)
 {
 	struct cairo_ctx *cc = ctx;
 	int w, h;
+	unsigned i;
 
 	end_common(cc, &w, &h);
 
 	cc->s = cairo_pdf_surface_create(cc->output_name, w, h);
 	cc->cr = cairo_create(cc->s);
 
-	set_color(cc->cr, COLOR_WHITE);
-	cairo_paint(cc->cr);
-
 	cairo_select_font_face(cc->cr, "Helvetica", CAIRO_FONT_SLANT_NORMAL,
 	    CAIRO_FONT_WEIGHT_BOLD);
 	cairo_set_line_width(cc->cr, 3);
 
+	for (i = 0; i != cc->n_sheets; i++) {
+		set_color(cc->cr, COLOR_WHITE);
+		cairo_paint(cc->cr);
+
+		layer_replay(cc->sheets + i);
+		layer_destroy(cc->sheets + i);
+
+		cairo_show_page(cc->cr);
+	}
+
 	layer_replay(&cc->layer);
 	layer_destroy(&cc->layer);
 
@@ -373,5 +403,6 @@ const struct gfx_ops cairo_pdf_ops = {
 	.text		= layer_text,
 	.text_width	= cr_text_width,
 	.init		= cr_pdf_init,
+	.new_sheet	= cr_pdf_new_sheet,
 	.end		= cr_pdf_end,
 };
diff --git a/sch2fig/layer.c b/sch2fig/layer.c
index 73c2c06..7b3eb6c 100644
--- a/sch2fig/layer.c
+++ b/sch2fig/layer.c
@@ -234,6 +234,12 @@ void layer_init(struct layer *layer, const struct gfx_ops *ops, void *user)
 }
 
 
+void layer_wipe(struct layer *layer)
+{
+	layer->objs = NULL;
+}
+
+
 void layer_replay(const struct layer *layer)
 {
 	const struct gfx_ops *ops = layer->ops;
diff --git a/sch2fig/layer.h b/sch2fig/layer.h
index 7a8cea7..e7caae4 100644
--- a/sch2fig/layer.h
+++ b/sch2fig/layer.h
@@ -49,6 +49,7 @@ void layer_text(void *ctx, int x, int y, const char *s, unsigned size,
     enum text_align align, int rot, unsigned color, unsigned layer);
 
 void layer_init(struct layer *layer, const struct gfx_ops *ops, void *user);
+void layer_wipe(struct layer *layer);
 void layer_replay(const struct layer *layer);
 void layer_bbox(const struct layer *layer, int *x, int *y, int *w, int *h);
 void layer_destroy(struct layer *layer);