Added DPI handing for graph font size. DPI is detected on duc-gui X11 and Glfw, and can be configured on the cmd line with the --dpi option for duc-cgi and duc-graph. Closes #201

Author: zevv

doc/duc.1

@@ -283,6 +283,10 @@ select database file to use [~/\.duc\.db]
 show number of files instead of file size
 .
 .TP
+\fB\-\-dpi=VAL\fR
+set destination resolution in DPI [96\.0]
+.
+.TP
 \fB\-f\fR, \fB\-\-format=VAL\fR
 select output format \fIpng|svg|pdf|html\fR [png]
 .
@@ -338,6 +342,10 @@ url of CSS style sheet to use instead of default CSS
 select database file to use [~/\.duc\.db]
 .
 .TP
+\fB\-\-dpi=VAL\fR
+set destination resolution in DPI [96\.0]
+.
+.TP
 \fB\-\-footer=VAL\fR
 select HTML file to include as footer
 .

doc/duc.1.html

@@ -278,6 +278,9 @@ Options for command `duc graph [options] [PATH]`:
   * `--count`:
     show number of files instead of file size
 
+  * `--dpi=VAL`:
+    set destination resolution in DPI [96.0]
+
   * `-f`, `--format=VAL`:
     select output format <png|svg|pdf|html> [png]
 
@@ -322,6 +325,9 @@ Options for command `duc cgi [options] [PATH]`:
   * `-d`, `--database=VAL`:
     select database file to use [~/.duc.db]
 
+  * `--dpi=VAL`:
+    set destination resolution in DPI [96.0]
+
   * `--footer=VAL`:
     select HTML file to include as footer
 

doc/duc.md

@@ -37,6 +37,7 @@ static int opt_levels = 4;
 static char *opt_palette = NULL;
 static bool opt_tooltip = false;
 static int opt_ring_gap = 4;
+static double opt_dpi = 96.0;
 
 static struct param *param_list = NULL;
 
@@ -526,6 +527,7 @@ static int cgi_main(duc *duc, int argc, char **argv)
 
 	duc_graph *graph = duc_graph_new_html(duc, stdout, 0);
 	duc_graph_set_size(graph, opt_size, opt_size);
+	duc_graph_set_dpi(graph, opt_dpi);
 	duc_graph_set_max_level(graph, opt_levels);
 	duc_graph_set_fuzz(graph, opt_fuzz);
 	duc_graph_set_palette(graph, palette);
@@ -549,6 +551,7 @@ static struct ducrc_option options[] = {
 	{ &opt_count,     "count",      0,  DUCRC_TYPE_BOOL,   "show number of files instead of file size" },
 	{ &opt_css_url,   "css-url",    0,  DUCRC_TYPE_STRING, "url of CSS style sheet to use instead of default CSS" },
 	{ &opt_database,  "database",  'd', DUCRC_TYPE_STRING, "select database file to use [~/.duc.db]" },
+	{ &opt_dpi,       "dpi",        0 , DUCRC_TYPE_DOUBLE, "set destination resolution in DPI [96.0]" },
 	{ &opt_footer,    "footer",     0,  DUCRC_TYPE_STRING, "select HTML file to include as footer" },
 	{ &opt_fuzz,      "fuzz",       0,  DUCRC_TYPE_DOUBLE, "use radius fuzz factor when drawing graph [0.7]" },
 	{ &opt_gradient,  "gradient",   0,  DUCRC_TYPE_BOOL,   "draw graph with color gradient" },

src/duc/cmd-cgi.c

@@ -27,6 +27,7 @@ static char *opt_palette = NULL;
 static enum duc_graph_palette palette = 0;
 static int opt_ring_gap = 4;
 static bool opt_gradient = false;
+static double opt_dpi = 96.0;
 
 #ifdef ENABLE_CAIRO
 static char *opt_format = "png";
@@ -119,6 +120,7 @@ static int graph_main(duc *duc, int argc, char **argv)
 	                   opt_apparent ? DUC_SIZE_TYPE_APPARENT : DUC_SIZE_TYPE_ACTUAL;
 
 	duc_graph_set_size(graph, opt_size, opt_size);
+	duc_graph_set_dpi(graph, opt_dpi);
 	duc_graph_set_fuzz(graph, opt_fuzz);
 	duc_graph_set_max_level(graph, opt_levels);
 	duc_graph_set_palette(graph, palette);
@@ -140,6 +142,7 @@ static struct ducrc_option options[] = {
 	{ &opt_apparent,  "apparent",  'a', DUCRC_TYPE_BOOL,   "Show apparent instead of actual file size" },
 	{ &opt_database,  "database",  'd', DUCRC_TYPE_STRING, "select database file to use [~/.duc.db]" },
 	{ &opt_count,     "count",      0,  DUCRC_TYPE_BOOL,   "show number of files instead of file size" },
+	{ &opt_dpi,       "dpi",        0 , DUCRC_TYPE_DOUBLE, "set destination resolution in DPI [96.0]" },
 	{ &opt_format,    "format",    'f', DUCRC_TYPE_STRING, 
 #ifdef ENABLE_CAIRO
 	                                                        "select output format <png|svg|pdf|html> [png]" },

src/duc/cmd-graph.c

@@ -260,10 +260,15 @@ int gui_main(duc *duc, int argc, char *argv[])
 	cs = cairo_xlib_surface_create(dpy, win, DefaultVisual(dpy, 0), win_w, win_h);
 	cr = cairo_create(cs);
 
-
-
 	graph = duc_graph_new_cairo(duc, cr);
 
+	int w_px = DisplayWidth(dpy, 0);
+	int w_mm = DisplayWidthMM(dpy, 0);
+	if(w_px && w_mm) {
+		double dpi = 25.4 * w_px / w_mm;
+		duc_graph_set_dpi(graph, dpi);
+	}
+
 	do_gui(duc, graph, dir);
 
 	duc_dir_close(dir);

src/duc/cmd-gui.c

@@ -201,6 +201,18 @@ int guigl_main(duc *duc, int argc, char *argv[])
 	sc2fb(window, &font_scale, NULL);
 	graph = duc_graph_new_opengl(duc, font_scale);
 
+	GLFWmonitor* mon = glfwGetPrimaryMonitor();
+	const GLFWvidmode* mode = glfwGetVideoMode(mon);
+	if(mode) {
+		int w_mm = 0, h_mm = 0;
+		glfwGetMonitorPhysicalSize(mon, &w_mm, &h_mm);
+		if(mode && mode->width && w_mm) {
+			double dpi = 25.4 * mode->width / w_mm;
+			printf("dpi %f\n", dpi);
+			duc_graph_set_dpi(graph, dpi);
+		}
+	}
+	
 	glfwSetKeyCallback(window, cb_keyboard);
 	glfwSetFramebufferSizeCallback(window, cb_winsize);
 	glfwSetMouseButtonCallback(window, cb_mouse_button);

src/duc/cmd-guigl.c

@@ -41,6 +41,7 @@ void duc_graph_free(duc_graph *g);
 
 void duc_graph_set_max_level(duc_graph *g, int max_level);
 void duc_graph_set_size(duc_graph *g, int w, int h);
+void duc_graph_set_dpi(duc_graph *g, double dpi);
 void duc_graph_set_position(duc_graph *g, double x, double y);
 void duc_graph_set_tooltip(duc_graph *g, double x, double y);
 void duc_graph_set_palette(duc_graph *g, enum duc_graph_palette p);

src/libduc-graph/duc-graph.h

@@ -31,6 +31,8 @@ struct duc_graph {
 
 	struct duc *duc;
 	double size;
+	double dpi;
+	double font_scale;
 	double cx, cy;
 	double pos_x, pos_y;
 	double width, height;

src/libduc-graph/graph-private.h

@@ -31,6 +31,7 @@ duc_graph *duc_graph_new(duc *duc)
 	g->duc = duc;
 	g->r_start = 100;
 	g->fuzz = 0;
+	duc_graph_set_dpi(g, 96);
 	duc_graph_set_max_level(g, 3);
 	duc_graph_set_size(g, 400, 400);
 
@@ -65,6 +66,13 @@ void duc_graph_set_size(duc_graph *g, int w, int h)
 }
 
 
+void duc_graph_set_dpi(duc_graph *g, double dpi)
+{
+	g->dpi = dpi;
+	g->font_scale = dpi / 96.0;
+}
+
+
 void duc_graph_set_position(duc_graph *g, double pos_x, double pos_y)
 {
 	g->pos_x = pos_x;
@@ -430,22 +438,22 @@ int duc_graph_draw(duc_graph *g, duc_dir *dir)
 
 	LL_FOREACH_SAFE(g->label_list, l, ln) {
 		if(g->backend)
-			g->backend->draw_text(g, (int)l->x, (int)l->y, FONT_SIZE_LABEL, l->text);
+			g->backend->draw_text(g, (int)l->x, (int)l->y, FONT_SIZE_LABEL * g->font_scale, l->text);
 		free(l->text);
 		free(l);
 	}
 
 	char *p = duc_dir_get_path(dir);
 	if(g->backend)
-		g->backend->draw_text(g, (int)g->cx, 10, FONT_SIZE_LABEL, p);
+		g->backend->draw_text(g, (int)g->cx, 10, FONT_SIZE_LABEL * g->font_scale, p);
 	free(p);
 
 	struct duc_size size;
 	duc_dir_get_size(dir, &size);
 	char siz[16];
 	duc_human_size(&size, g->size_type, g->bytes, siz, sizeof siz);
 	if(g->backend)
-		g->backend->draw_text(g, (int)g->cx, (int)g->cy, FONT_SIZE_CENTER, siz);
+		g->backend->draw_text(g, (int)g->cx, (int)g->cy, FONT_SIZE_CENTER * g->font_scale, siz);
 
 	if(g->tooltip_r < g->r_start) {
 		gen_tooltip(g, &size, NULL, DUC_FILE_TYPE_DIR);