Make GtkValueGraph use Cairo

git-svn-id: svn://cook.msm.cam.ac.uk:745/diff-tomo/dtr@182 bf6ca9ba-c028-0410-8290-897cf20841d1

1 files changed, 81 insertions, 64 deletions

diff --git a/src/gtk-valuegraph.c b/src/gtk-valuegraph.c
index a847946..47c6060 100644
--- a/src/gtk-valuegraph.c
+++ b/src/gtk-valuegraph.c
@@ -62,47 +62,67 @@ static void gtk_value_graph_class_init(GtkValueGraphClass *class) {
 	
 }
 
-
 static gint gtk_value_graph_draw(GtkWidget *graph, GdkEventExpose *event, gpointer data) {
 
 	GtkValueGraph *vg;
-	unsigned int bw_left, bw_right, bw_top, bw_bottom;
+	double bw_left, bw_right, bw_top, bw_bottom;
 	PangoLayout *y0_layout;
 	PangoLayout *y1_layout;
 	PangoLayout *x0_layout;
 	PangoLayout *x1_layout;
 	PangoRectangle y0_extent, y1_extent, x0_extent, x1_extent;
-	unsigned int width, height;
+	double width, height;
 	char tmp[32];
-	unsigned int i;
-	
+	int i;
+	cairo_t *cr;
+	PangoFontDescription *desc;
+	double scale;
+  	
 	vg = GTK_VALUE_GRAPH(graph);
 	
+	cr = gdk_cairo_create(graph->window);
+	
 	/* Blank white background */
-	gdk_draw_rectangle(graph->window, graph->style->white_gc, TRUE, 0, 0, graph->allocation.width, graph->allocation.height);
+	cairo_rectangle(cr, 0.0, 0.0, graph->allocation.width, graph->allocation.height);
+	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
+	cairo_fill(cr);
 	
 	/* Create PangoLayouts for labels */
-	y0_layout = gtk_widget_create_pango_layout(graph, "0");
-	pango_layout_get_pixel_extents(y0_layout, NULL, &y0_extent);
-
+	desc = pango_font_description_from_string("Sans, Normal, 10");
+	if ( fabs(log(vg->ymax)/log(10)) < 3 ) {
+		snprintf(tmp, 31, "%.4f", vg->ymin);
+	} else {
+		snprintf(tmp, 31, "%1.1e", vg->ymin);
+	}
+	y0_layout = pango_cairo_create_layout(cr);
+	pango_layout_set_text(y0_layout, tmp, -1);
+	pango_layout_set_font_description(y0_layout, desc);
+  	pango_layout_get_pixel_extents(y0_layout, NULL, &y0_extent);
+	
 	if ( fabs(log(vg->ymax)/log(10)) < 3 ) {
 		snprintf(tmp, 31, "%.4f", vg->ymax);
 	} else {
 		snprintf(tmp, 31, "%1.1e", vg->ymax);
 	}
-	y1_layout = gtk_widget_create_pango_layout(graph, tmp);
-	pango_layout_get_pixel_extents(y1_layout, NULL, &y1_extent);
+	y1_layout = pango_cairo_create_layout(cr);
+	pango_layout_set_text(y1_layout, tmp, -1);
+	pango_layout_set_font_description(y1_layout, desc);
+  	pango_layout_get_pixel_extents(y1_layout, NULL, &y1_extent);
+	
+	x0_layout = pango_cairo_create_layout(cr);
+	pango_layout_set_text(x0_layout, "0", -1);
+	pango_layout_set_font_description(x0_layout, desc);
+  	pango_layout_get_pixel_extents(x0_layout, NULL, &x0_extent);
 	
-	x0_layout = gtk_widget_create_pango_layout(graph, "0");
-	pango_layout_get_pixel_extents(x0_layout, NULL, &x0_extent);
-
 	if ( vg->xmax < 1000 ) {
-		snprintf(tmp, 31, "%i", vg->xmax);
+		snprintf(tmp, 31, "%.0f", vg->xmax);
 	} else {
 		snprintf(tmp, 31, "%1.1e", (double)vg->xmax);
 	}
-	x1_layout = gtk_widget_create_pango_layout(graph, tmp);
-	pango_layout_get_pixel_extents(x1_layout, NULL, &x1_extent);
+	x1_layout = pango_cairo_create_layout(cr);
+	pango_layout_set_text(x1_layout, tmp, -1);
+	pango_layout_set_font_description(x1_layout, desc);
+  	pango_layout_get_pixel_extents(x1_layout, NULL, &x1_extent);
 	
 	/* Determine border widths */
 	bw_left = 1+((y1_extent.width > y0_extent.width) ? y1_extent.width : y0_extent.width);
@@ -113,29 +133,40 @@ static gint gtk_value_graph_draw(GtkWidget *graph, GdkEventExpose *event, gpoint
 	height = graph->allocation.height;
 	
 	/* Draw axis lines */
-	gdk_draw_line(graph->window, graph->style->black_gc, bw_left, height-1-bw_bottom, bw_left, bw_top);
-	gdk_draw_line(graph->window, graph->style->black_gc, bw_left, height-1-bw_bottom, width-1-bw_right, height-1-bw_bottom);
+	cairo_new_path(cr);
+	cairo_move_to(cr, bw_left+0.5, height-1-bw_bottom+0.5);
+	cairo_line_to(cr, bw_left+0.5, bw_top+0.5);
+	cairo_move_to(cr, bw_left+0.5, height-1-bw_bottom+0.5);
+	cairo_line_to(cr, width-1-bw_right+0.5, height-1-bw_bottom+0.5);
+	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+	cairo_set_line_width(cr, 1.0);
+	cairo_stroke(cr);
 
 	/* Label axes */
-	gdk_draw_layout(graph->window, graph->style->black_gc, 1+bw_left-x0_extent.width/2, height-1-bw_bottom, x0_layout);
-	gdk_draw_layout(graph->window, graph->style->black_gc, width-bw_right-x1_extent.width/2, height-1-bw_bottom, x1_layout);
-	gdk_draw_layout(graph->window, graph->style->black_gc, bw_left-y0_extent.width-1, height-1-bw_bottom-y0_extent.height/2, y0_layout);
-	gdk_draw_layout(graph->window, graph->style->black_gc, bw_left-y1_extent.width-1, 1, y1_layout);
+	cairo_new_path(cr);
+	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+	cairo_move_to(cr, 1+bw_left-x0_extent.width/2, height-1-bw_bottom);
+	pango_cairo_layout_path(cr, x0_layout);
+	cairo_move_to(cr, width-bw_right-x1_extent.width/2, height-1-bw_bottom);
+	pango_cairo_layout_path(cr, x1_layout);
+	cairo_move_to(cr, bw_left-y0_extent.width-1, height-1-bw_bottom-y0_extent.height/2);
+	pango_cairo_layout_path(cr, y0_layout);
+	cairo_move_to(cr, bw_left-y1_extent.width-1, 1);
+	pango_cairo_layout_path(cr, y1_layout);
+	cairo_fill(cr);
 	
 	/* Plot data */
-	for ( i=0; i<vg->n; i++ ) {
-		
-		unsigned int x, y;
-		double xd, yd;
-		
-		xd = (((double)width-bw_left-bw_right)/(double)vg->xmax)*(double)(i+1);	/* Graph axes go from 1 */
-		x = bw_left + xd;
-		yd = (((double)height-bw_top-bw_bottom)/(double)vg->ymax)*(double)vg->data[i];
-		y = height-bw_bottom - yd;
-		
-		gdk_draw_point(graph->window, graph->style->black_gc, x, y);
+	cairo_new_path(cr);
+	scale = (height-bw_top-bw_bottom)/(vg->ymax-vg->ymin);
+	cairo_move_to(cr, bw_left, height-bw_bottom-1-scale*(vg->data[0]-vg->ymin));
+	for ( i=1; i<vg->n; i++ ) {
 		
+		cairo_line_to(cr, bw_left+((double)i/vg->xmax)*(width-bw_left-bw_right), height-bw_bottom-1-scale*(vg->data[i]-vg->ymin));
+	
 	}
+	cairo_set_line_width(cr, 1.0);
+	cairo_set_source_rgb(cr, 0.0, 0.0, 1.0);
+	cairo_stroke(cr);
 	
 	return 0;
 
@@ -186,45 +217,31 @@ static double gtk_value_graph_peak(double *data, unsigned int n) {
 
 }
 
-/* Calculate the best range for a axis with maximum value n */
-static double gtk_value_graph_axis_max(double n) {
+static double gtk_value_graph_min(double *data, unsigned int n) {
 
-	double mantissa, exponent, test;
-return n;	
-	if ( n == 0 ) return 1;
-	
-	/* Convert to standard form */
-	exponent = rint(log(n)/log(10));
-	mantissa = n / pow(10, exponent);
-
-	/* Check if the value can be exactly represented */
-	test = mantissa * 10;
-	test = rint(test);
-	test /= 10;
-	if ( fabs(test - mantissa) > 0.001 ) {
-	
-		/* Round the mantissa upwards */
-		mantissa += 0.1;
-		mantissa *= 10;
-		mantissa = rint(mantissa);
-		mantissa /= 10;
-	
-	} /* Else don't touch it */
+	unsigned int i;
+	double min;
 	
-	return mantissa*pow(10, exponent);
+	if ( n == 0 ) return 0;
 	
+	min = +HUGE_VAL;
+	for ( i=0; i<n; i++ ) {
+		if ( data[i] < min ) min = data[i];
+	}
+
+	return min;
+
 }
 
 void gtk_value_graph_set_data(GtkValueGraph *vg, double *data, unsigned int n) {
 	
-	double dmax;
-	
-	/* Recalculate axes */
-	dmax = gtk_value_graph_peak(data, n);
 	vg->data = data;
 	vg->n = n;
-	vg->xmax = gtk_value_graph_axis_max(n);
-	vg->ymax = gtk_value_graph_axis_max(dmax);
+
+	/* Recalculate axes */
+	vg->xmax = n;
+	vg->ymax = gtk_value_graph_peak(data, n);
+	vg->ymin = gtk_value_graph_min(data, n);
 	
 	//printf("n=%i, dmax=%f => xmax=%i, ymax=%f\n", n, dmax, vg->xmax, vg->ymax);