--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libmlk-ui/ui/gridmenu.c	Fri Oct 01 20:30:00 2021 +0200
@@ -0,0 +1,298 @@
+/*
+ * gridmenu.c -- GUI grid menu
+ *
+ * Copyright (c) 2020-2021 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 <string.h>
+
+#include <core/event.h>
+#include <core/maths.h>
+#include <core/painter.h>
+#include <core/panic.h>
+#include <core/texture.h>
+#include <core/trace.h>
+
+#include "ui_p.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
+positionate(struct gridmenu *menu)
+{
+	const struct theme *theme = THEME(menu);
+	struct gridmenu_texture *gtex = &menu->tex;
+	unsigned int vreq, hreq;
+
+	/* Compute which item has the bigger width to create a spacing. */
+	for (size_t i = 0; i < GRIDMENU_ENTRY_MAX; ++i) {
+		unsigned int lw, lh;
+
+		gtex->labels[i].theme = theme;
+		gtex->labels[i].flags = LABEL_FLAGS_SHADOW;
+
+		if (!(gtex->labels[i].text = menu->menu[i]))
+			continue;
+
+		label_query(&gtex->labels[i], &lw, &lh);
+		gtex->eltw = lw > gtex->eltw ? lw : gtex->eltw;
+		gtex->elth = lh > gtex->elth ? lh : gtex->elth;
+	}
+
+	vreq = (theme->padding * 2) + (gtex->elth * menu->nrows);
+	hreq = (theme->padding * 2) + (gtex->eltw * menu->ncols);
+
+	/* Compute spacing between elements. */
+	if (hreq > menu->w) {
+		tracef(_("gridmenu width is too small: %u < %u"), menu->w, vreq);
+		gtex->spaceh = 1;
+	} else {
+		hreq -= theme->padding * 2;
+		gtex->spaceh = (menu->w - hreq) / menu->ncols;
+	}
+
+	if (vreq > menu->h) {
+		tracef(_("gridmenu height is too small: %u < %u"), menu->h, vreq);
+		gtex->spacev = 1;
+	} else {
+		vreq -= theme->padding * 2;
+		gtex->spacev = (menu->h - vreq) / menu->nrows;
+	}
+
+	/* This is the whole height. */
+	gtex->relh  = theme->padding * 2;
+	gtex->relh += gtex->elth * (GRIDMENU_ENTRY_MAX / menu->ncols);
+	gtex->relh += gtex->spacev * (GRIDMENU_ENTRY_MAX / menu->ncols);
+}
+
+static void
+repaint_frame(struct gridmenu *menu)
+{
+	const struct frame f = {
+		.x = 0,
+		.y = menu->tex.rely,
+		.w = menu->w,
+		.h = menu->h,
+		.theme = menu->theme,
+	};
+
+	frame_draw(&f);
+}
+
+static void
+repaint_labels(struct gridmenu *menu)
+{
+	struct theme theme;
+	unsigned int r = 0, c = 0;
+
+	/* Copy theme to change color if selected. */
+	theme_shallow(&theme, THEME(menu));
+
+	for (size_t i = 0; i < GRIDMENU_ENTRY_MAX; ++i) {
+		struct label *l = &menu->tex.labels[i];
+
+		if (i == menu->selected)
+			theme.colors[THEME_COLOR_NORMAL] = THEME(menu)->colors[THEME_COLOR_SELECTED];
+		else
+			theme.colors[THEME_COLOR_NORMAL] = THEME(menu)->colors[THEME_COLOR_NORMAL];
+
+		l->theme = &theme;
+		l->x = theme.padding + (c * menu->tex.eltw) + (c * menu->tex.spaceh);
+		l->y = theme.padding + (r * menu->tex.elth) + (r * menu->tex.spacev);
+
+		if (++c >= menu->ncols) {
+			++r;
+			c = 0;
+		}
+
+		if (l->text)
+			label_draw(l);
+	}
+}
+
+static void
+repaint(struct gridmenu *menu)
+{
+	struct texture *tex = &menu->tex.texture;
+
+	if (!texture_ok(tex) && texture_new(tex, menu->w, menu->tex.relh) < 0)
+		panic();
+
+	PAINTER_BEGIN(tex);
+
+	painter_clear();
+	repaint_frame(menu);
+	repaint_labels(menu);
+
+	PAINTER_END();
+}
+
+static void
+zoom(struct gridmenu *menu)
+{
+	struct gridmenu_texture *tex = &menu->tex;
+	struct label *cur = &tex->labels[menu->selected];
+
+	/* Readjust relative position. */
+	if ((unsigned int)cur->y > tex->rely + menu->h || cur->y < tex->rely)
+		tex->rely = cur->y - THEME(menu)->padding;
+}
+
+static void
+handle_keydown(struct gridmenu *menu, const struct event_key *key)
+{
+	assert(key->type == EVENT_KEYDOWN);
+
+	const struct index idx = get_index(menu);
+	const unsigned int save = menu->selected;
+
+	switch (key->key) {
+	case KEY_UP:
+		if (idx.row > 0)
+			menu->selected -= menu->ncols;
+		break;
+	case KEY_RIGHT:
+		if (idx.col + 1U < menu->ncols)
+			menu->selected += 1;
+		break;
+	case KEY_DOWN:
+		if (idx.row + 1U < GRIDMENU_ENTRY_MAX / menu->ncols)
+			menu->selected += menu->ncols;
+		break;
+	case KEY_LEFT:
+		if (idx.col > 0)
+			menu->selected -= 1;
+		break;
+	case KEY_ENTER:
+		menu->state = GRIDMENU_STATE_ACTIVATED;
+		break;
+	default:
+		break;
+	}
+
+	if (save != menu->selected)
+		gridmenu_repaint(menu);
+}
+
+static void
+handle_clickdown(struct gridmenu *menu, const struct event_click *click)
+{
+	assert(click->type == EVENT_CLICKDOWN);
+
+	const unsigned int save = menu->selected;
+
+	for (size_t i = 0; i < GRIDMENU_ENTRY_MAX; ++i) {
+		const struct label *l = &menu->tex.labels[i];
+		const int x = menu->x + l->x;
+		const int y = menu->y + l->y - menu->tex.rely;
+		const unsigned int w = menu->tex.eltw;
+		const unsigned int h = menu->tex.elth;
+
+		if (maths_is_boxed(x, y, w, h, click->x, click->y)) {
+			menu->selected = i;
+			break;
+		}
+	}
+
+	/* A click immediately active the widget. */
+	if (save != menu->selected) {
+		gridmenu_repaint(menu);
+		menu->state = GRIDMENU_STATE_ACTIVATED;
+	}
+}
+
+void
+gridmenu_reset(struct gridmenu *menu)
+{
+	assert(menu);
+
+	menu->state = GRIDMENU_STATE_NONE;
+}
+
+void
+gridmenu_repaint(struct gridmenu *menu)
+{
+	assert(menu);
+	assert(GRIDMENU_ENTRY_MAX % menu->ncols == 0);
+
+	/* Re-compute positions. */
+	positionate(menu);
+
+	/* Zoom to the appropriate y-relative. */
+	zoom(menu);
+
+	/* Redraw. */
+	repaint(menu);
+}
+
+void
+gridmenu_handle(struct gridmenu *menu, const union event *ev)
+{
+	assert(menu);
+	assert(ev);
+
+	switch (ev->type) {
+	case EVENT_KEYDOWN:
+		handle_keydown(menu, &ev->key);
+		break;
+	case EVENT_CLICKDOWN:
+		handle_clickdown(menu, &ev->click);
+		break;
+	default:
+		break;
+	}
+}
+
+void
+gridmenu_draw(const struct gridmenu *menu)
+{
+	assert(menu);
+	assert(menu->nrows > 0 && menu->ncols > 0);
+	assert(texture_ok(&menu->tex.texture));
+
+	texture_scale(&menu->tex.texture,
+	    0, menu->tex.rely, menu->w, menu->h,
+	    menu->x, menu->y, menu->w, menu->h, 0.0);
+}
+
+void
+gridmenu_finish(struct gridmenu *menu)
+{
+	assert(menu);
+
+	if (texture_ok(&menu->tex.texture))
+		texture_finish(&menu->tex.texture);
+
+	memset(menu, 0, sizeof (*menu));
+}