--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-ui/mlk/ui/gridmenu.c	Sat Oct 15 21:19:25 2022 +0200
@@ -0,0 +1,287 @@
+/*
+ * gridmenu.c -- GUI grid menu
+ *
+ * Copyright (c) 2020-2022 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <math.h>
+#include <string.h>
+
+#include <mlk/core/event.h>
+#include <mlk/core/maths.h>
+#include <mlk/core/painter.h>
+#include <mlk/core/panic.h>
+#include <mlk/core/texture.h>
+#include <mlk/core/trace.h>
+
+#include "frame.h"
+#include "label.h"
+#include "gridmenu.h"
+#include "theme.h"
+
+#define THEME(m) ((m)->theme ? (m)->theme : theme_default())
+
+struct index {
+	unsigned int row;
+	unsigned int col;
+};
+
+static struct index
+get_index(const struct gridmenu *menu)
+{
+	return (struct index) {
+		.row = menu->selected / menu->ncols,
+		.col = menu->selected % menu->ncols
+	};
+}
+
+static void
+geometry(struct gridmenu *menu)
+{
+	const struct theme *theme = THEME(menu);
+	struct label label = {
+		.theme = theme,
+		.flags = LABEL_FLAGS_SHADOW
+	};
+	unsigned int reqw = 0, reqh = 0, lw, lh;
+
+	/* Compute which item has the bigger width/height to create a spacing. */
+	menu->eltw = menu->elth = 0;
+	menu->spacew = menu->spaceh = 0;
+
+	for (size_t i = 0; i < menu->itemsz; ++i) {
+		if (!(label.text = menu->items[i]))
+			continue;
+
+
+		label_query(&label, &lw, &lh);
+
+		menu->eltw = fmax(menu->eltw, lw);
+		menu->elth = fmax(menu->elth, lh);
+	}
+
+	/* Total texture size required to draw items. */
+	reqw = (theme->padding * 2) + (menu->eltw * menu->ncols);
+	reqh = (theme->padding * 2) + (menu->elth * menu->nrows);
+
+	/*
+	 * Compute spacing between elements. We remove the padding because it
+	 * is outside of the elements.
+	 */
+	if (reqw > menu->w) {
+		tracef("gridmenu width is too small: %u < %u", menu->w, reqw);
+		menu->spacew = 1;
+	} else if (menu->ncols > 1) {
+		reqw -= theme->padding * 2;
+		menu->spacew = (menu->w - reqw) / menu->ncols;
+	}
+
+	if (reqh > menu->h) {
+		tracef("gridmenu height is too small: %u < %u", menu->h, reqh);
+		menu->spaceh = 1;
+	} else if (menu->nrows > 1) {
+		reqh -= theme->padding * 2;
+		menu->spaceh = (menu->h - reqh) / menu->nrows;
+	}
+}
+
+static void
+draw_frame(const struct gridmenu *menu)
+{
+	const struct frame f = {
+		.x = menu->x,
+		.y = menu->y,
+		.w = menu->w,
+		.h = menu->h,
+		.theme = menu->theme,
+	};
+
+	frame_draw(&f);
+}
+
+static void
+draw_labels(const struct gridmenu *menu)
+{
+	size_t pagesz, pagenr, item, c = 0, r = 0;
+	struct label label = {0};
+	const struct theme *theme = THEME(menu);
+
+	label.theme = theme;
+	label.flags = LABEL_FLAGS_SHADOW;
+
+	/*
+	 * Select the first top-left column based on the current selection and
+	 * the number of rows/columns.
+	 */
+	pagesz = menu->nrows * menu->ncols;
+	pagenr = menu->selected / pagesz;
+
+	for (size_t i = 0; i < pagesz; ++i) {
+		item = i + pagenr * pagesz;
+
+		if (item >= menu->itemsz || !menu->items[item])
+			continue;
+
+		label.text = menu->items[item];
+		label.x = menu->x + theme->padding + (c * menu->eltw) + (c * menu->spacew);
+		label.y = menu->y + theme->padding + (r * menu->elth) + (r * menu->spaceh);
+
+		if (i == menu->selected % pagesz)
+			label.flags |= LABEL_FLAGS_SELECTED;
+		else
+			label.flags &= ~(LABEL_FLAGS_SELECTED);
+
+		label_draw(&label);
+
+		if (++c >= menu->ncols) {
+			++r;
+			c = 0;
+		}
+	}
+}
+
+static int
+handle_keydown(struct gridmenu *menu, const struct event_key *key)
+{
+	assert(key->type == EVENT_KEYDOWN);
+
+	const struct index idx = get_index(menu);
+	int validate = 0;
+
+	switch (key->key) {
+	case KEY_UP:
+		if (idx.row > 0)
+			menu->selected -= menu->ncols;
+		break;
+	case KEY_RIGHT:
+		if (menu->selected + 1U < menu->itemsz)
+			menu->selected += 1;
+		break;
+	case KEY_DOWN:
+		if (idx.row + 1U < menu->itemsz / menu->ncols)
+			menu->selected += menu->ncols;
+		else
+			menu->selected = menu->itemsz - 1;
+		break;
+	case KEY_LEFT:
+		if (idx.col > 0)
+			menu->selected -= 1;
+		break;
+	case KEY_ENTER:
+		validate = 1;
+		break;
+	default:
+		break;
+	}
+
+	return validate;
+}
+
+static int
+handle_clickdown(struct gridmenu *menu, const struct event_click *click)
+{
+	assert(click->type == EVENT_CLICKDOWN);
+
+	const struct theme *theme = THEME(menu);
+	size_t pagesz, pagenr, selected, c = 0, r = 0;
+	int x, y;
+
+	pagesz = menu->nrows * menu->ncols;
+	pagenr = menu->selected / pagesz;
+
+	for (size_t i = 0; i < pagesz; ++i) {
+		x = menu->x + theme->padding + (c * menu->eltw) + (c * menu->spacew);
+		y = menu->y + theme->padding + (r * menu->elth) + (r * menu->spaceh);
+
+		if (maths_is_boxed(x, y, menu->eltw, menu->elth, click->x, click->y)) {
+			selected  = c + r * menu->ncols;
+			selected += pagesz * pagenr;
+
+			if (selected < menu->itemsz) {
+				menu->selected = selected;
+				return 1;
+			}
+		}
+
+		if (++c >= menu->ncols) {
+			++r;
+			c = 0;
+		}
+	}
+
+	return 0;
+}
+
+void
+gridmenu_init(struct gridmenu *menu,
+              unsigned int nr,
+              unsigned int nc,
+              const char * const *items,
+              size_t itemsz)
+{
+	assert(menu);
+	assert(nr);
+	assert(nc);
+
+	memset(menu, 0, sizeof (*menu));
+
+	menu->nrows = nr;
+	menu->ncols = nc;
+	menu->items = items;
+	menu->itemsz = itemsz;
+}
+
+void
+gridmenu_resize(struct gridmenu *menu, int x, int y, unsigned int w, unsigned int h)
+{
+	assert(menu);
+
+	menu->x = x;
+	menu->y = y;
+	menu->w = w;
+	menu->h = h;
+
+	geometry(menu);
+}
+
+int
+gridmenu_handle(struct gridmenu *menu, const union event *ev)
+{
+	assert(menu);
+	assert(ev);
+
+	switch (ev->type) {
+	case EVENT_KEYDOWN:
+		return handle_keydown(menu, &ev->key);
+		break;
+	case EVENT_CLICKDOWN:
+		return handle_clickdown(menu, &ev->click);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+void
+gridmenu_draw(const struct gridmenu *menu)
+{
+	assert(menu);
+
+	draw_frame(menu);
+	draw_labels(menu);
+}