Align titles to baseline

This does the following:

* Adds a baseline argument to get_text_size (the baseline is the
distance from the top of the texture to the baseline).
* Stores the baseline in the container when calculating the title
height.
* Takes the baseline into account when calculating the config's max font
height.
* When rendering, pads the textures according to the baseline so they
line up.

11 files changed, 49 insertions, 32 deletions

diff --git a/common/pango.c b/common/pango.c
index 92703f80..ea71ac4a 100644
--- a/common/pango.c
+++ b/common/pango.c
@@ -103,7 +103,7 @@ PangoLayout *get_pango_layout(cairo_t *cairo, const char *font,
 }
 
 void get_text_size(cairo_t *cairo, const char *font, int *width, int *height,
-		double scale, bool markup, const char *fmt, ...) {
+		int *baseline, double scale, bool markup, const char *fmt, ...) {
 	static char buf[2048];
 
 	va_list args;
@@ -116,6 +116,9 @@ void get_text_size(cairo_t *cairo, const char *font, int *width, int *height,
 	PangoLayout *layout = get_pango_layout(cairo, font, buf, scale, markup);
 	pango_cairo_update_layout(cairo, layout);
 	pango_layout_get_pixel_size(layout, width, height);
+	if (baseline) {
+		*baseline = pango_layout_get_baseline(layout) / PANGO_SCALE;
+	}
 	g_object_unref(layout);
 }
 
diff --git a/include/pango.h b/include/pango.h
index 4492f01e..09a535a5 100644
--- a/include/pango.h
+++ b/include/pango.h
@@ -20,7 +20,7 @@ int escape_markup_text(const char *src, char *dest, int dest_length);
 PangoLayout *get_pango_layout(cairo_t *cairo, const char *font,
 		const char *text, double scale, bool markup);
 void get_text_size(cairo_t *cairo, const char *font, int *width, int *height,
-		double scale, bool markup, const char *fmt, ...);
+		int *baseline, double scale, bool markup, const char *fmt, ...);
 void pango_printf(cairo_t *cairo, const char *font,
 		double scale, bool markup, const char *fmt, ...);
 
diff --git a/include/sway/config.h b/include/sway/config.h
index 2fef0081..b52bb681 100644
--- a/include/sway/config.h
+++ b/include/sway/config.h
@@ -349,6 +349,7 @@ struct sway_config {
 	enum sway_container_layout default_layout;
 	char *font;
 	size_t font_height;
+	size_t font_baseline;
 	bool pango_markup;
 	size_t urgent_timeout;
 	enum sway_fowa focus_on_window_activation;
diff --git a/include/sway/tree/container.h b/include/sway/tree/container.h
index 6efecf7c..2735daa3 100644
--- a/include/sway/tree/container.h
+++ b/include/sway/tree/container.h
@@ -117,6 +117,7 @@ struct sway_container {
 	struct wlr_texture *title_unfocused;
 	struct wlr_texture *title_urgent;
 	size_t title_height;
+	size_t title_baseline;
 
 	struct {
 		struct wl_signal destroy;
diff --git a/sway/config.c b/sway/config.c
index 89701640..6ff4da03 100644
--- a/sway/config.c
+++ b/sway/config.c
@@ -807,22 +807,31 @@ int workspace_output_cmp_workspace(const void *a, const void *b) {
 	return lenient_strcmp(wsa->workspace, wsb->workspace);
 }
 
-static void find_font_height_iterator(struct sway_container *container,
-		void *data) {
+static void find_font_height_iterator(struct sway_container *con, void *data) {
+	size_t amount_below_baseline = con->title_height - con->title_baseline;
+	size_t extended_height = config->font_baseline + amount_below_baseline;
+	if (extended_height > config->font_height) {
+		config->font_height = extended_height;
+	}
+}
+
+static void find_baseline_iterator(struct sway_container *con, void *data) {
 	bool *recalculate = data;
 	if (*recalculate) {
-		container_calculate_title_height(container);
+		container_calculate_title_height(con);
 	}
-	if (container->title_height > config->font_height) {
-		config->font_height = container->title_height;
+	if (con->title_baseline > config->font_baseline) {
+		config->font_baseline = con->title_baseline;
 	}
 }
 
 void config_update_font_height(bool recalculate) {
 	size_t prev_max_height = config->font_height;
 	config->font_height = 0;
+	config->font_baseline = 0;
 
-	root_for_each_container(find_font_height_iterator, &recalculate);
+	root_for_each_container(find_baseline_iterator, &recalculate);
+	root_for_each_container(find_font_height_iterator, NULL);
 
 	if (config->font_height != prev_max_height) {
 		arrange_root();
diff --git a/sway/debug-tree.c b/sway/debug-tree.c
index 973c6d88..9644f4e5 100644
--- a/sway/debug-tree.c
+++ b/sway/debug-tree.c
@@ -84,7 +84,7 @@ static int draw_node(cairo_t *cairo, struct sway_node *node,
 		struct sway_node *focus, int x, int y) {
 	int text_width, text_height;
 	char *buffer = get_string(node);
-	get_text_size(cairo, "monospace", &text_width, &text_height,
+	get_text_size(cairo, "monospace", &text_width, &text_height, NULL,
 		1, false, buffer);
 	cairo_save(cairo);
 	cairo_rectangle(cairo, x + 2, y, text_width - 2, text_height);
diff --git a/sway/desktop/render.c b/sway/desktop/render.c
index ecac262e..8a6f63aa 100644
--- a/sway/desktop/render.c
+++ b/sway/desktop/render.c
@@ -466,12 +466,12 @@ static void render_titlebar(struct sway_output *output,
 			&texture_box.width, &texture_box.height);
 		title_ob_width = texture_box.width;
 
-		// The title texture might be shorter than the config->font_height, in
-		// which case we need to pad it as evenly as possible above and below.
-		int ob_padding_total = config->font_height * output_scale -
-			texture_box.height;
-		int ob_padding_above = floor(ob_padding_total / 2);
-		int ob_padding_below = ceil(ob_padding_total / 2);
+		// The title texture might be shorter than the config->font_height,
+		// in which case we need to pad it above and below.
+		int ob_padding_above = (config->font_baseline - con->title_baseline)
+			* output_scale;
+		int ob_padding_below = (config->font_height - con->title_height)
+			* output_scale - ob_padding_above;
 
 		// Render texture
 		texture_box.x = (x - output_x + TITLEBAR_H_PADDING) * output_scale;
diff --git a/sway/tree/container.c b/sway/tree/container.c
index cbbb1f56..ccd79f0e 100644
--- a/sway/tree/container.c
+++ b/sway/tree/container.c
@@ -455,8 +455,8 @@ static void update_title_texture(struct sway_container *con,
 	int height = con->title_height * scale;
 
 	cairo_t *c = cairo_create(NULL);
-	get_text_size(c, config->font, &width, NULL, scale, config->pango_markup,
-			"%s", con->formatted_title);
+	get_text_size(c, config->font, &width, NULL, NULL, scale,
+			config->pango_markup, "%s", con->formatted_title);
 	cairo_destroy(c);
 
 	cairo_surface_t *surface = cairo_image_surface_create(
@@ -505,10 +505,12 @@ void container_calculate_title_height(struct sway_container *container) {
 	}
 	cairo_t *cairo = cairo_create(NULL);
 	int height;
-	get_text_size(cairo, config->font, NULL, &height, 1, config->pango_markup,
-			"%s", container->formatted_title);
+	int baseline;
+	get_text_size(cairo, config->font, NULL, &height, &baseline, 1,
+			config->pango_markup, "%s", container->formatted_title);
 	cairo_destroy(cairo);
 	container->title_height = height;
+	container->title_baseline = baseline;
 }
 
 /**
diff --git a/sway/tree/view.c b/sway/tree/view.c
index 312c62d1..53215b40 100644
--- a/sway/tree/view.c
+++ b/sway/tree/view.c
@@ -935,7 +935,8 @@ static void update_marks_texture(struct sway_view *view,
 	int height = view->container->title_height * scale;
 
 	cairo_t *c = cairo_create(NULL);
-	get_text_size(c, config->font, &width, NULL, scale, false, "%s", buffer);
+	get_text_size(c, config->font, &width, NULL, NULL, scale, false,
+			"%s", buffer);
 	cairo_destroy(c);
 
 	cairo_surface_t *surface = cairo_image_surface_create(
diff --git a/swaybar/render.c b/swaybar/render.c
index 702e863c..7303e70f 100644
--- a/swaybar/render.c
+++ b/swaybar/render.c
@@ -33,8 +33,8 @@ static uint32_t render_status_line_error(cairo_t *cairo,
 	int ws_vertical_padding = WS_VERTICAL_PADDING * output->scale;
 
 	int text_width, text_height;
-	get_text_size(cairo, config->font,
-			&text_width, &text_height, output->scale, false, "%s", error);
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
+			output->scale, false, "%s", error);
 
 	uint32_t ideal_height = text_height + ws_vertical_padding * 2;
 	uint32_t ideal_surface_height = ideal_height / output->scale;
@@ -63,7 +63,7 @@ static uint32_t render_status_line_text(cairo_t *cairo,
 			config->colors.focused_statusline : config->colors.statusline);
 
 	int text_width, text_height;
-	get_text_size(cairo, config->font, &text_width, &text_height,
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
 			output->scale, config->pango_markup, "%s", text);
 
 	int ws_vertical_padding = WS_VERTICAL_PADDING * output->scale;
@@ -126,7 +126,7 @@ static uint32_t render_status_block(cairo_t *cairo,
 	uint32_t height = surface_height * output->scale;
 
 	int text_width, text_height;
-	get_text_size(cairo, config->font, &text_width, &text_height,
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
 			output->scale, block->markup, "%s", block->full_text);
 
 	int margin = 3 * output->scale;
@@ -157,7 +157,7 @@ static uint32_t render_status_block(cairo_t *cairo,
 	int sep_width, sep_height;
 	if (!edge) {
 		if (config->sep_symbol) {
-			get_text_size(cairo, config->font, &sep_width, &sep_height,
+			get_text_size(cairo, config->font, &sep_width, &sep_height, NULL,
 					output->scale, false, "%s", config->sep_symbol);
 			uint32_t _ideal_height = sep_height + ws_vertical_padding * 2;
 			uint32_t _ideal_surface_height = _ideal_height / output->scale;
@@ -297,7 +297,7 @@ static uint32_t render_binding_mode_indicator(cairo_t *cairo,
 	uint32_t height = surface_height * output->scale;
 
 	int text_width, text_height;
-	get_text_size(cairo, config->font, &text_width, &text_height,
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
 			output->scale, config->mode_pango_markup,
 			"%s", mode);
 
@@ -379,7 +379,7 @@ static uint32_t render_workspace_button(cairo_t *cairo,
 	uint32_t height = surface_height * output->scale;
 
 	int text_width, text_height;
-	get_text_size(cairo, config->font, &text_width, &text_height,
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
 			output->scale, config->pango_markup, "%s", name);
 
 	int ws_vertical_padding = WS_VERTICAL_PADDING * output->scale;
diff --git a/swaynag/render.c b/swaynag/render.c
index 766409e4..7db9fe60 100644
--- a/swaynag/render.c
+++ b/swaynag/render.c
@@ -12,7 +12,7 @@ static uint32_t render_message(cairo_t *cairo, struct swaynag *swaynag) {
 	height -= swaynag->type->bar_border_thickness * swaynag->scale;
 
 	int text_width, text_height;
-	get_text_size(cairo, swaynag->type->font, &text_width, &text_height,
+	get_text_size(cairo, swaynag->type->font, &text_width, &text_height, NULL,
 			swaynag->scale, true, "%s", swaynag->message);
 
 	int padding = swaynag->type->message_padding * swaynag->scale;
@@ -34,7 +34,7 @@ static uint32_t render_message(cairo_t *cairo, struct swaynag *swaynag) {
 static void render_details_scroll_button(cairo_t *cairo,
 		struct swaynag *swaynag, struct swaynag_button *button) {
 	int text_width, text_height;
-	get_text_size(cairo, swaynag->type->font, &text_width, &text_height,
+	get_text_size(cairo, swaynag->type->font, &text_width, &text_height, NULL,
 			swaynag->scale, true, "%s", button->text);
 
 	int border = swaynag->type->button_border_thickness * swaynag->scale;
@@ -60,10 +60,10 @@ static void render_details_scroll_button(cairo_t *cairo,
 static int get_detailed_scroll_button_width(cairo_t *cairo,
 		struct swaynag *swaynag) {
 	int up_width, down_width, temp_height;
-	get_text_size(cairo, swaynag->type->font, &up_width, &temp_height,
+	get_text_size(cairo, swaynag->type->font, &up_width, &temp_height, NULL,
 			swaynag->scale, true,
 			"%s", swaynag->details.button_up.text);
-	get_text_size(cairo, swaynag->type->font, &down_width, &temp_height,
+	get_text_size(cairo, swaynag->type->font, &down_width, &temp_height, NULL,
 			swaynag->scale, true,
 			"%s", swaynag->details.button_down.text);
 
@@ -179,7 +179,7 @@ static uint32_t render_button(cairo_t *cairo, struct swaynag *swaynag,
 	struct swaynag_button *button = swaynag->buttons->items[button_index];
 
 	int text_width, text_height;
-	get_text_size(cairo, swaynag->type->font, &text_width, &text_height,
+	get_text_size(cairo, swaynag->type->font, &text_width, &text_height, NULL,
 			swaynag->scale, true, "%s", button->text);
 
 	int border = swaynag->type->button_border_thickness * swaynag->scale;