From e8131140bc963d8f19e4d8691a6b9447bff94534 Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Sat, 17 Sep 2011 09:17:42 -0700
Subject: [PATCH] Add some scaling controls with plus/minus keybindings.

Total cheese in that the symbols (braces and clefs) don't change size yet,
but at least the line widths snap to nice integers.
---
 scherzo.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
 score.c   | 25 ++++++++++++++++++-------
 2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/scherzo.c b/scherzo.c
index c49584c..f6669ed 100644
--- a/scherzo.c
+++ b/scherzo.c
@@ -17,6 +17,7 @@
  */
 
 #include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
 
 #include "score.h"
 
@@ -41,8 +42,8 @@ on_delete_event_quit (unused (GtkWidget *widget),
 }
 
 static int
-on_expose_event_draw (GtkWidget	*widget,
-		      unused (GdkEventExpose *event),
+on_expose_event_draw (GtkWidget *widget,
+		      unused (GdkEventExpose *expose),
 		      void * user_data)
 {
     scherzo_t *scherzo = user_data;
@@ -63,6 +64,7 @@ on_expose_event_draw (GtkWidget	*widget,
 
     /* Add some padding on the left/right */
     cairo_translate (cr, pad, pad);
+    score_set_staff_height (score, scherzo->staff_height);
     score_set_width (score, widget_width - 2 * pad);
 
     score_draw (score, cr);
@@ -70,6 +72,39 @@ on_expose_event_draw (GtkWidget	*widget,
     return TRUE;
 }
 
+static int
+on_key_press_event (GtkWidget *widget,
+		    GdkEventKey *key,
+		    void *user_data)
+{
+    scherzo_t *scherzo = user_data;
+
+    switch (key->keyval) {
+    case GDK_KEY_plus:
+    case GDK_KEY_KP_Add:
+    case GDK_KEY_equal:
+    case GDK_KEY_KP_Equal:
+	scherzo->staff_height += 4;
+	gtk_widget_queue_draw (widget);
+	return TRUE;
+	break;
+    case GDK_KEY_minus:
+    case GDK_KEY_KP_Subtract:
+	scherzo->staff_height -= 4;
+	gtk_widget_queue_draw (widget);
+	return TRUE;
+	break;
+    case GDK_KEY_q:
+    case GDK_KEY_Q:
+    case GDK_KEY_Escape:
+	gtk_main_quit ();
+	return FALSE;
+    }
+
+    /* Allow the event to propagate to other handlers. */
+    return FALSE;
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -80,7 +115,7 @@ main (int argc, char *argv[])
     gtk_init (&argc, &argv);
 
     scherzo.score = score_create (NULL);
-    scherzo.staff_height = 20;
+    scherzo.staff_height = 24;
     score_set_staff_height (scherzo.score, scherzo.staff_height);
 
     window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
@@ -97,6 +132,10 @@ main (int argc, char *argv[])
     g_signal_connect (drawing_area, "expose-event",  
 		      G_CALLBACK (on_expose_event_draw),
 		      &scherzo);
+
+    g_signal_connect (window, "key-press-event",  
+		      G_CALLBACK (on_key_press_event),
+		      &scherzo);
     
     gtk_widget_show_all (window);
     
diff --git a/score.c b/score.c
index 598c298..5bb7909 100644
--- a/score.c
+++ b/score.c
@@ -28,6 +28,9 @@ struct score
     /* Height of one space within a staff */
     int space_height;
 
+    /* Minimal line width for staff lines */
+    int line_width;
+
     /* Full width of staff */
     int width;
 };
@@ -48,6 +51,11 @@ score_set_staff_height (score_t *score, int height)
 {
     score->space_height = (int) height / 4;
     score->staff_height = score->space_height * 4;
+
+    score->line_width = score->space_height / 15;
+    if (score->line_width == 0)
+	score->line_width = 1;
+
     return score->staff_height;
 }
 
@@ -96,15 +104,17 @@ _draw_staff (score_t *score, cairo_t *cr, score_clef_t clef)
     cairo_show_glyphs (cr, &glyph, 1);
 
     cairo_rectangle (cr,
-		     0.5, 0.5,
-		     score->width - 1.0, score->space_height * 4);
+		     score->line_width / 2.0,
+		     score->line_width / 2.0,
+		     score->width - score->line_width,
+		     score->space_height * 4);
     
     for (i = 1; i < 4; i++) {
-	cairo_move_to (cr, 0, i * score->space_height + 0.5);
+	cairo_move_to (cr, 0, i * score->space_height + score->line_width / 2.0);
 	cairo_rel_line_to (cr, score->width, 0);
     }
 
-    cairo_set_line_width (cr, 1.0);
+    cairo_set_line_width (cr, score->line_width);
 
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
     cairo_stroke (cr);
@@ -148,11 +158,12 @@ _draw_grand_staff (score_t *score, cairo_t *cr)
 
     /* Vertical lines at each end */
     cairo_rectangle (cr,
-		     0.5, 0.5,
-		     score->width - 1.0,
+		     score->line_width / 2.0,
+		     score->line_width / 2.0,
+		     score->width - score->line_width,
 		     score->staff_height * 3);
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
-    cairo_set_line_width (cr, 1.0);
+    cairo_set_line_width (cr, score->line_width);
     cairo_stroke (cr);
 
     /* Top staff */
-- 
2.43.0