Convert to using Cairo scale.

Instead of scaling various theme parameters ourselves, just set the
scale in Cairo. This shouldn't result in any visible changes, but lays
the ground work for fractional scaling support.

2 files changed, 37 insertions, 21 deletions

diff --git a/src/entry_backend/harfbuzz.c b/src/entry_backend/harfbuzz.c
index ae26d67..3bb8a8f 100644
--- a/src/entry_backend/harfbuzz.c
+++ b/src/entry_backend/harfbuzz.c
@@ -84,7 +84,7 @@ static void setup_hb_buffer(hb_buffer_t *buffer)
  * Render a hb_buffer with Cairo, and return the extents of the rendered text
  * in Cairo units.
  */
-static cairo_text_extents_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer)
+static cairo_text_extents_t render_hb_buffer(cairo_t *cr, hb_font_extents_t *font_extents, hb_buffer_t *buffer, double scale)
 {
 	cairo_save(cr);
 
@@ -92,9 +92,7 @@ static cairo_text_extents_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer)
 	 * Cairo uses y-down coordinates, but HarfBuzz uses y-up, so we
 	 * shift the text down by its ascent height to compensate.
 	 */
-	cairo_font_extents_t font_extents;
-	cairo_font_extents(cr, &font_extents);
-	cairo_translate(cr, 0, font_extents.ascent);
+	cairo_translate(cr, 0, font_extents->ascender / 64.0);
 
 	unsigned int glyph_count;
 	hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(buffer, &glyph_count);
@@ -107,12 +105,17 @@ static cairo_text_extents_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer)
 		/*
 		 * The coordinates returned by HarfBuzz are in 26.6 fixed-point
 		 * format, so we divide by 64.0 (2^6) to get floats.
+		 *
+		 * For whatever reason, the coordinates are also scaled by
+		 * Cairo's scale factor, so we have to also divide by the scale
+		 * factor to account for this.
 		 */
 		cairo_glyphs[i].index = glyph_info[i].codepoint;
-		cairo_glyphs[i].x = x + glyph_pos[i].x_offset / 64.0;
-		cairo_glyphs[i].y = y - glyph_pos[i].y_offset / 64.0;
-		x += glyph_pos[i].x_advance / 64.0;
-		y -= glyph_pos[i].y_advance / 64.0;
+		cairo_glyphs[i].x = x + glyph_pos[i].x_offset / 64.0 / scale;
+		cairo_glyphs[i].y = y - glyph_pos[i].y_offset / 64.0 / scale;
+
+		x += glyph_pos[i].x_advance / 64.0 / scale;
+		y -= glyph_pos[i].y_advance / 64.0 / scale;
 	}
 
 	cairo_show_glyphs(cr, cairo_glyphs, glyph_count);
@@ -121,7 +124,7 @@ static cairo_text_extents_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer)
 	cairo_glyph_extents(cr, cairo_glyphs, glyph_count, &extents);
 
 	/* Account for the shifted baseline in our returned text extents. */
-	extents.y_bearing += font_extents.ascent;
+	extents.y_bearing += font_extents->ascender / 64.0;
 
 	free(cairo_glyphs);
 
@@ -143,7 +146,7 @@ static cairo_text_extents_t render_text(
 	setup_hb_buffer(hb->hb_buffer);
 	hb_buffer_add_utf8(hb->hb_buffer, text, -1, 0, -1);
 	hb_shape(hb->hb_font, hb->hb_buffer, hb->hb_features, hb->num_features);
-	return render_hb_buffer(cr, hb->hb_buffer);
+	return render_hb_buffer(cr, &hb->hb_font_extents, hb->hb_buffer, hb->scale);
 }
 
 
@@ -259,7 +262,7 @@ static cairo_text_extents_t render_input(
 	setup_hb_buffer(hb->hb_buffer);
 	hb_buffer_add_utf32(hb->hb_buffer, text, -1, 0, -1);
 	hb_shape(hb->hb_font, hb->hb_buffer, hb->hb_features, hb->num_features);
-	cairo_text_extents_t extents = render_hb_buffer(cr, hb->hb_buffer);
+	cairo_text_extents_t extents = render_hb_buffer(cr, &hb->hb_font_extents, hb->hb_buffer, hb->scale);
 
 	/*
 	 * If the cursor is at the end of text, we need to account for it in
@@ -304,7 +307,7 @@ static cairo_text_extents_t render_input(
 		color = theme->foreground_color;
 		cairo_set_source_rgba(cr, color.r, color.g, color.b, color.a);
 
-		render_hb_buffer(cr, hb->hb_buffer);
+		render_hb_buffer(cr, &hb->hb_font_extents, hb->hb_buffer, hb->scale);
 	}
 
 	if (!cursor_theme->show) {
@@ -385,8 +388,8 @@ static cairo_text_extents_t render_input(
 			cursor_end += x_advance;
 		}
 		/* Convert from HarfBuzz 26.6 fixed-point to float. */
-		cursor_x = cursor_start / 64.0;
-		cursor_width = (cursor_end - cursor_start) / 64.0;
+		cursor_x = cursor_start / 64.0 / hb->scale;
+		cursor_width = (cursor_end - cursor_start) / 64.0 / hb->scale;
 	}
 
 	cairo_save(cr);
@@ -405,7 +408,7 @@ static cairo_text_extents_t render_input(
 			cairo_translate(cr, -cursor_x, 0);
 			color = cursor_theme->text_color;
 			cairo_set_source_rgba(cr, color.r, color.g, color.b, color.a);
-			render_hb_buffer(cr, hb->hb_buffer);
+			render_hb_buffer(cr, &hb->hb_font_extents, hb->hb_buffer, hb->scale);
 			break;
 		case CURSOR_STYLE_UNDERSCORE:
 			cairo_translate(cr, 0, cursor_theme->underline_depth);
@@ -444,6 +447,7 @@ void entry_backend_harfbuzz_init(
 	struct entry_backend_harfbuzz *hb = &entry->harfbuzz;
 	cairo_t *cr = entry->cairo[0].cr;
 	uint32_t font_size = floor(entry->font_size * PT_TO_DPI);
+	cairo_surface_get_device_scale(entry->cairo[0].surface, &hb->scale, NULL);
 
 	/*
 	 * Setting up our font has three main steps:
@@ -582,6 +586,11 @@ void entry_backend_harfbuzz_init(
 	log_debug("Creating Harfbuzz buffer.\n");
 	hb->hb_buffer = hb_buffer_create();
 
+	hb_font_get_h_extents(hb->hb_font, &hb->hb_font_extents);
+	if (hb->hb_font_extents.line_gap == 0) {
+		hb->hb_font_extents.line_gap = (hb->hb_font_extents.ascender - hb->hb_font_extents.descender);
+	}
+
 	log_debug("Creating Cairo font.\n");
 	hb->cairo_face = cairo_ft_font_face_create_for_ft_face(hb->ft_face, 0);
 
@@ -619,13 +628,17 @@ void entry_backend_harfbuzz_update(struct entry *entry)
 	cairo_t *cr = entry->cairo[entry->index].cr;
 	cairo_text_extents_t extents;
 
-	cairo_font_extents_t font_extents;
-	cairo_font_extents(cr, &font_extents);
-
 	cairo_save(cr);
 
 	/* Render the prompt */
 	extents = render_text_themed(cr, entry, entry->prompt_text, &entry->prompt_theme);
+	{
+		struct entry_backend_harfbuzz *hb = &entry->harfbuzz;
+		hb_buffer_clear_contents(hb->hb_buffer);
+		setup_hb_buffer(hb->hb_buffer);
+		hb_buffer_add_utf8(hb->hb_buffer, "test", -1, 0, -1);
+		hb_shape(hb->hb_font, hb->hb_buffer, hb->hb_features, hb->num_features);
+	}
 
 	cairo_translate(cr, extents.x_advance, 0);
 	cairo_translate(cr, entry->prompt_padding, 0);
@@ -683,7 +696,7 @@ void entry_backend_harfbuzz_update(struct entry *entry)
 		if (entry->horizontal) {
 			cairo_translate(cr, extents.x_advance + entry->result_spacing, 0);
 		} else {
-			cairo_translate(cr, 0, font_extents.height + entry->result_spacing);
+			cairo_translate(cr, 0, entry->harfbuzz.hb_font_extents.line_gap / 64.0 + entry->result_spacing);
 		}
 		if (entry->num_results == 0) {
 			if (size_overflows(entry, 0, 0)) {
@@ -729,7 +742,7 @@ void entry_backend_harfbuzz_update(struct entry *entry)
 				 * The height of the text doesn't change, so
 				 * we don't need to re-measure it each time.
 				 */
-				if (size_overflows(entry, 0, font_extents.height)) {
+				if (size_overflows(entry, 0, entry->harfbuzz.hb_font_extents.line_gap / 64.0)) {
 					break;
 				} else {
 					extents = render_text_themed(cr, entry, result, theme);
@@ -871,7 +884,7 @@ void entry_backend_harfbuzz_update(struct entry *entry)
 					rounded_rectangle(
 							cr,
 							ceil(extents.width + padding.left + padding.right),
-							ceil(font_extents.height + padding.top + padding.bottom),
+							ceil(entry->harfbuzz.hb_font_extents.line_gap / 64.0 + padding.top + padding.bottom),
 							entry->selection_theme.background_corner_radius
 							);
 					cairo_fill(cr);
diff --git a/src/entry_backend/harfbuzz.h b/src/entry_backend/harfbuzz.h
index 17b5945..acaa2eb 100644
--- a/src/entry_backend/harfbuzz.h
+++ b/src/entry_backend/harfbuzz.h
@@ -19,12 +19,15 @@ struct entry_backend_harfbuzz {
 	cairo_font_face_t *cairo_face;
 
 	hb_font_t *hb_font;
+	hb_font_extents_t hb_font_extents;
 	hb_buffer_t *hb_buffer;
 	hb_variation_t hb_variations[MAX_FONT_VARIATIONS];
 	hb_feature_t hb_features[MAX_FONT_FEATURES];
 	uint8_t num_variations;
 	uint8_t num_features;
 
+	double scale;
+
 	bool disable_hinting;
 };