Revamp gui component

`gui` was tighly coupled to game logic, and could not be extended for
other purposes. Therefore, a generic GUI implementation, loosely
inspired by well-known GUI frameworks such as GTK, is now provided, with
the following properties:

- Does not depend on dynamic or static memory allocation, only automatic
(i.e., stack) memory allocation required.
- Portable among existing implementations.
- Simple to extend.
- Tiny memory footprint.

`gui` is now composed by GUI elements that can be chained to form a tree
structure. This is useful e.g.: to calculate X/Y coordinates for a given
GUI element given its parent(s).

This commit also refactors the older implementation, moving
game-specific logic into `player` and making use of the new component.

3 files changed, 0 insertions, 139 deletions

diff --git a/src/button/CMakeLists.txt b/src/button/CMakeLists.txt
deleted file mode 100644
index 1e6e693..0000000
--- a/src/button/CMakeLists.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-add_library(button "src/button.c")
-target_include_directories(button PUBLIC "inc")
-target_link_libraries(button PUBLIC gfx PRIVATE font)
diff --git a/src/button/inc/button.h b/src/button/inc/button.h
deleted file mode 100644
index 062cb07..0000000
--- a/src/button/inc/button.h
+++ /dev/null
@@ -1,36 +0,0 @@
-#ifndef BUTTON_H
-#define BUTTON_H
-
-#include <gfx.h>
-#include <stdbool.h>
-
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
-enum
-{
-    BUTTON_LEFT,
-    BUTTON_MID,
-    BUTTON_RIGHT,
-
-    MAX_BUTTON_SPRITES
-};
-
-struct button
-{
-    const char *text;
-    short x, y, w;
-};
-
-bool button_is_pressed(const struct button *b);
-int button_render(const struct button *b);
-
-extern struct sprite button_sprites[MAX_BUTTON_SPRITES];
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* BUTTON_H */
diff --git a/src/button/src/button.c b/src/button/src/button.c
deleted file mode 100644
index 9508d5c..0000000
--- a/src/button/src/button.c
+++ /dev/null
@@ -1,100 +0,0 @@
-#include <button.h>
-#include <font.h>
-#include <gfx.h>
-
-struct sprite button_sprites[MAX_BUTTON_SPRITES];
-
-bool button_is_pressed(const struct button *const b)
-{
-    return false;
-}
-
-static int render_left(const struct button *const b, short *const x)
-{
-    sprite_get_or_ret(s, -1);
-
-    if (sprite_clone(&button_sprites[BUTTON_LEFT], s))
-        return -1;
-
-    s->x = b->x;
-    s->y = b->y;
-    sprite_sort(s);
-    *x = s->x + s->w;
-    return 0;
-}
-
-static int render_mid(const struct button *const b, short *const x)
-{
-    const short mid_w = button_sprites[BUTTON_MID].w;
-    const short lw = button_sprites[BUTTON_LEFT].w;
-    const short rw = button_sprites[BUTTON_RIGHT].w;
-    const short w = b->w - lw - rw;
-
-    if (w > 0)
-    {
-        const short rem_mid = w > 0 ? w % mid_w : 0;
-        const short whole_mid = w / mid_w;
-        const short n_mid = rem_mid ? whole_mid + 1 : whole_mid;
-
-        for (struct
-            {
-                size_t i;
-                short x;
-            } a = {.i = 0, .x = lw};
-            a.i < n_mid;
-            a.i++, a.x += mid_w)
-        {
-            sprite_get_or_ret(m, -1);
-
-            if (sprite_clone(&button_sprites[BUTTON_MID], m))
-                return -1;
-
-            m->x = *x;
-            m->y = b->y;
-
-            if (rem_mid && a.i + 1 == n_mid)
-                m->w = rem_mid;
-            else
-                m->w = mid_w;
-
-            sprite_sort(m);
-            *x += m->w;
-        }
-    }
-
-    return 0;
-}
-
-static int render_right(const struct button *const b, const short *const x)
-{
-    sprite_get_or_ret(s, -1);
-
-    if (sprite_clone(&button_sprites[BUTTON_RIGHT], s))
-        return -1;
-
-    s->x = *x;
-    s->y = b->y;
-    sprite_sort(s);
-    return 0;
-}
-
-static int render_text(const struct button *const b)
-{
-    const short x = b->x + button_sprites[BUTTON_LEFT].w,
-        y = b->y + (button_sprites[BUTTON_MID].h >> 2);
-
-    return font_printf(FONT, x, y, "%s", b->text) < 0;
-}
-
-int button_render(const struct button *const b)
-{
-    short x;
-
-    if (render_left(b, &x)
-        || render_mid(b, &x)
-        || render_right(b, &x)
-        || render_text(b))
-        return -1;
-
-    return 0;
-}