Separated arranging the layout to own state and function

1 files changed, 73 insertions, 34 deletions

diff --git a/text.c b/text.c
index 38ae0b1..187c301 100644
--- a/text.c
+++ b/text.c
@@ -1,5 +1,6 @@
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <cairo.h>
 #include <cairo-xcb.h>
@@ -40,21 +41,29 @@ struct State
 	xcb_screen_t * s;
 	xcb_visualtype_t * v;
 	xcb_window_t w;
-	cairo_t * ctx;
+	cairo_t * ctx;  // TODO-maybe: separate drawing context, application state and xcb state?
 	cairo_surface_t * surface;
 };
 
 enum Actions
 {
 	ACTION_REDRAW = 1 << 0,
-	ACTION_RELAYOUT = 1 << 1,
+	ACTION_ARRANGE = 1 << 1,
 	ACTION_CLOSE = 1 << 2,
 };
 
+struct Layout
+{
+	PangoFontDescription * desc;
+	int size;
+	PangoLayout ** v;
+};
+
 int setup(struct State *);
-void finalize(struct State *);
+void finalize(struct State *, struct Layout *);
 int handle(struct State *, xcb_generic_event_t *);
-void draw(struct State *, union Command *);
+void arrange(struct State *, struct Layout *, union Command[]);
+void draw(struct State *, struct Layout *);
 xcb_visualtype_t * find_visual(xcb_screen_t *);
 
 static const int MARGIN = 20;
@@ -83,17 +92,20 @@ int main(int argc, const char ** argv)
 		dprintf(2, "Could not connect to X server\n");  // TODO: Helpful (specific) errors.
 		return 1;
 	}
+	struct Layout layout = {.desc = NULL, .size = 0, .v = NULL};
+	arrange(&state, &layout, body);
 	for (;;)
 	{
 		xcb_generic_event_t * e = xcb_wait_for_event(state.c);  // TODO: All events first, then flagged actions.
 		int actions = handle(&state, e);  // Obviously, right now this may have at most one action.
 		if (ACTION_CLOSE & actions)
 			break;
-		// if (ACTION_RELAYOUT & actions)  TODO: Implement separate layouting.
+		if (ACTION_ARRANGE & actions)
+			arrange(&state, &layout, body);
 		if (ACTION_REDRAW & actions)
-			draw(&state, body);
+			draw(&state, &layout);
 	}
-	finalize(&state);
+	finalize(&state, &layout);
 }
 
 
@@ -123,8 +135,12 @@ int setup(struct State * state)
 }
 
 
-void finalize(struct State * state)
+void finalize(struct State * state, struct Layout * layout)
 {
+	pango_font_description_free(layout->desc);
+	for (int i = 0; i < layout->size; ++i)
+		g_object_unref(layout->v[i]);
+	free(layout->v);
 	cairo_destroy(state->ctx);
 	cairo_surface_destroy(state->surface);
 	xcb_disconnect(state->c);
@@ -144,7 +160,7 @@ int handle(struct State * state, xcb_generic_event_t * e)
 		break;
 	case XCB_CONFIGURE_NOTIFY:
 		;
-		actions |= ACTION_RELAYOUT;
+		actions |= ACTION_ARRANGE;
 		xcb_configure_notify_event_t * conf = (xcb_configure_notify_event_t *) e;
 		if (state->width != conf->width || state->height != conf->height)
 		{
@@ -175,41 +191,47 @@ xcb_visualtype_t * find_visual(xcb_screen_t * screen)
 }
 
 
-void draw(struct State * state, union Command * body)
+void arrange(struct State * state, struct Layout * layout, union Command body[])
 {
-	cairo_set_source_rgb(state->ctx, 1., 1., 1.);
-	cairo_paint(state->ctx);
-	PangoFontDescription * desc = pango_font_description_from_string(FONT);
-	cairo_set_source_rgb(state->ctx, 0., 0., 0.);
-	int y = MARGIN;
-	PangoAttrList * attrs = pango_attr_list_new();  // TODO: Store layouts and only relayout if needed.
-	for (union Command * command = body; COMMAND_DONE != command->type; ++command)
+	if (NULL == layout->desc)
+		layout->desc = pango_font_description_from_string(FONT);
+	int size = 0;
+	for (union Command * c = body; COMMAND_DONE != c->type; ++c)
+		if (COMMAND_BLOCK == c->type)
+			size++;
+	if (size != layout->size)
 	{
-		switch (command->type)
+		for (int i = 0; i < layout->size; ++i)
+			g_object_unref(layout->v[i]);  /// TODO-maybe: Reuse already existing layouts of blocks.
+		layout->v = malloc(sizeof(PangoLayout *) * size);
+		if (NULL == layout->v)
+			abort();  // TODO: Be more graceful?
+		for (int i = 0; i < size; ++i)
+			layout->v[i] = pango_cairo_create_layout(state->ctx);
+		layout->size = size;
+	}
+	PangoAttrList * attrs = pango_attr_list_new();
+	int i = 0;
+	for (union Command * c = body; COMMAND_DONE != c->type; ++c)
+	{
+		switch (c->type)
 		{
 		case COMMAND_SPAN:
 			;
 			PangoAttribute * attr = pango_attr_foreground_new(0x0000, 0x0000, 0xffff);
-			attr->start_index = command->span.position;
-			attr->end_index = command->span.position + command->span.length;
+			attr->start_index = c->span.position;
+			attr->end_index = c->span.position + c->span.length;
 			pango_attr_list_change(attrs, attr);
 			break;
 		case COMMAND_BLOCK:
-			cairo_move_to(state->ctx, MARGIN, y);
-			PangoLayout * layout = pango_cairo_create_layout(state->ctx);
-			pango_layout_set_attributes(layout, attrs);
+			pango_layout_set_attributes(layout->v[i], attrs);  // TODO-maybe: Don't reset everything?
 			pango_attr_list_unref(attrs);
 			attrs = pango_attr_list_new();
-			pango_layout_set_font_description(layout, desc);
-			pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
-			pango_layout_set_width(layout, (state->width - 2 * MARGIN) * PANGO_SCALE);
-			pango_layout_set_text(layout, command->block.data, command->block.length);
-			pango_cairo_update_layout(state->ctx, layout);
-			pango_cairo_show_layout(state->ctx, layout);
-			int height;
-			pango_layout_get_pixel_size(layout, NULL, &height);
-			y += height + MARGIN;
-			g_object_unref(layout);
+			pango_layout_set_font_description(layout->v[i], layout->desc);
+			pango_layout_set_wrap(layout->v[i], PANGO_WRAP_WORD);
+			pango_layout_set_width(layout->v[i], (state->width - 2 * MARGIN) * PANGO_SCALE);
+			pango_layout_set_text(layout->v[i], c->block.data, c->block.length);
+			i++;
 			break;
 		case COMMAND_NOTHING:
 		default:
@@ -217,7 +239,24 @@ void draw(struct State * state, union Command * body)
 		}
 	}
 	pango_attr_list_unref(attrs);
-	pango_font_description_free(desc);
+}
+
+
+void draw(struct State * state, struct Layout * layout)
+{
+	cairo_set_source_rgb(state->ctx, 1., 1., 1.);
+	cairo_paint(state->ctx);
+	cairo_set_source_rgb(state->ctx, 0., 0., 0.);
+	int y = MARGIN;
+	for (int i = 0; i < layout->size; ++i)
+	{
+		cairo_move_to(state->ctx, MARGIN, y);
+		pango_cairo_update_layout(state->ctx, layout->v[i]);
+		pango_cairo_show_layout(state->ctx, layout->v[i]);
+		int height;
+		pango_layout_get_pixel_size(layout->v[i], NULL, &height);
+		y += height + MARGIN;
+	}
 	cairo_surface_flush(state->surface);
 	xcb_flush(state->c);
 }