Use GTK_UNIT_INCH when printing to provide consistency across OS

Tests have shown that the most multi-platform way to do printing with GTK is
to use GTK_UNIT_INCH (or GTK_UNIT_MM) with GtkPrintOperation. Tested on
Linux, OSX, Windows.

However this requires the appropriate scaling for Pango and Cairo to be done,
with separate plotting logic for printing and drawing on the screen. To achieve
that, profile.c:plot() now accepts a scaling parameter from type
"scale_mode_t" defined in "display.h".

Also due to new scale, small decimal numbers (such as 6.12345) cannot be well
stored in "cairo_rectangle_int_t" therefore it is replaced with
"cairo_rectangle_t", which uses doubles to provide Cairo with a drawing
area.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>

Minor whitespace cleanup.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 29 insertions, 9 deletions

diff --git a/profile.c b/profile.c
index 0039867ef..3a3df043c 100644
--- a/profile.c
+++ b/profile.c
@@ -16,6 +16,11 @@
 int selected_dive = 0;
 char zoomed_plot = 0;
 
+static double plot_scale = SCALE_SCREEN;
+
+#define cairo_set_line_width_scaled(cr, w) \
+	cairo_set_line_width((cr), (w) * plot_scale);
+
 typedef enum { STABLE, SLOW, MODERATE, FAST, CRAZY } velocity_t;
 
 /* Plot info with smoothing, velocity indication
@@ -245,7 +250,7 @@ static void plot_text(struct graphics_context *gc, const text_render_options_t *
 	vsnprintf(buffer, sizeof(buffer), fmt, args);
 	va_end(args);
 
-	cairo_set_font_size(cr, tro->size);
+	cairo_set_font_size(cr, tro->size * plot_scale);
 	cairo_font_extents(cr, &fe);
 	cairo_text_extents(cr, buffer, &extents);
 	dx = tro->hpos * extents.width + extents.x_bearing;
@@ -485,7 +490,7 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
 	gc->leftx = 0; gc->rightx = maxtime;
 	gc->topy = 0; gc->bottomy = 1.0;
 	set_source_rgba(gc, TIME_GRID);
-	cairo_set_line_width(gc->cr, 2);
+	cairo_set_line_width_scaled(gc->cr, 2);
 
 	for (i = incr; i < maxtime; i += incr) {
 		move_to(gc, i, 0);
@@ -542,13 +547,13 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
 	gc->topy = 0; gc->bottomy = maxdepth;
 
 	cairo_pattern_t *pat;
-	pat = cairo_pattern_create_linear (0.0, 0.0,  0.0, 256.0);
+	pat = cairo_pattern_create_linear (0.0, 0.0,  0.0, 256.0 * plot_scale);
 	pattern_add_color_stop_rgba (gc, pat, 1, DEPTH_BOTTOM);
 	pattern_add_color_stop_rgba (gc, pat, 0, DEPTH_TOP);
 
 	cairo_set_source(gc->cr, pat);
 	cairo_pattern_destroy(pat);
-	cairo_set_line_width(gc->cr, 2);
+	cairo_set_line_width_scaled(gc->cr, 2);
 
 	entry = pi->entry;
 	move_to(gc, 0, 0);
@@ -655,7 +660,7 @@ static void plot_temperature_profile(struct graphics_context *gc, struct plot_in
 	if (!setup_temperature_limits(gc, pi))
 		return;
 
-	cairo_set_line_width(gc->cr, 2);
+	cairo_set_line_width_scaled(gc->cr, 2);
 	set_source_rgba(gc, TEMP_PLOT);
 	for (i = 0; i < pi->nr; i++) {
 		struct plot_data *entry = pi->entry + i;
@@ -730,7 +735,7 @@ static void plot_cylinder_pressure(struct graphics_context *gc, struct plot_info
 	if (!get_cylinder_pressure_range(gc, pi))
 		return;
 
-	cairo_set_line_width(gc->cr, 2);
+	cairo_set_line_width_scaled(gc->cr, 2);
 
 	for (i = 0; i < pi->nr; i++) {
 		int mbar;
@@ -1374,13 +1379,28 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
 	return analyze_plot_info(pi);
 }
 
-void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, struct dive *dive)
+static void plot_set_scale(scale_mode_t scale)
+{
+	switch (scale) {
+	default:
+	case SC_SCREEN:
+		plot_scale = SCALE_SCREEN;
+		break;
+	case SC_PRINT:
+		plot_scale = SCALE_PRINT;
+		break;
+	}
+}
+
+void plot(struct graphics_context *gc, cairo_rectangle_t *drawing_area, struct dive *dive, scale_mode_t scale)
 {
 	struct plot_info *pi;
 	static struct sample fake[4];
 	struct sample *sample = dive->sample;
 	int nr = dive->samples;
 
+	plot_set_scale(scale);
+
 	if (!nr) {
 		/* The dive has no samples, so create a few fake ones.  This assumes an
 		ascent/descent rate of 9 m/min, which is just below the limit for FAST. */
@@ -1401,7 +1421,7 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
 	pi = create_plot_info(dive, nr, sample);
 
 	cairo_translate(gc->cr, drawing_area->x, drawing_area->y);
-	cairo_set_line_width(gc->cr, 1);
+	cairo_set_line_width_scaled(gc->cr, 1);
 	cairo_set_line_cap(gc->cr, CAIRO_LINE_CAP_ROUND);
 	cairo_set_line_join(gc->cr, CAIRO_LINE_JOIN_ROUND);
 
@@ -1435,7 +1455,7 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
 	gc->topy = 0; gc->bottomy = 1.0;
 
 	set_source_rgba(gc, BOUNDING_BOX);
-	cairo_set_line_width(gc->cr, 1);
+	cairo_set_line_width_scaled(gc->cr, 1);
 	move_to(gc, 0, 0);
 	line_to(gc, 0, 1);
 	line_to(gc, 1, 1);