--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libui/ui/theme.h	Thu Oct 15 10:32:18 2020 +0200
@@ -0,0 +1,194 @@
+/*
+ * theme.h -- abstract theming
+ *
+ * Copyright (c) 2020 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.
+ */
+
+#ifndef MOLKO_THEME_H
+#define MOLKO_THEME_H
+
+/**
+ * \file theme.h
+ * \brief Abstract theming.
+ */
+
+#include <stdbool.h>
+
+struct checkbox;
+struct button;
+struct font;
+struct frame;
+struct label;
+
+/**
+ * \brief Font component.
+ */
+enum theme_font {
+	THEME_FONT_DEBUG,       /*!< Font for debug messages. */
+	THEME_FONT_INTERFACE,   /*!< Font for interface elements. */
+	THEME_FONT_LAST         /*!< Unused. */
+};
+
+/**
+ * \brief Theme colors.
+ */
+enum theme_color {
+	THEME_COLOR_DEBUG,      /*!< Debug color font. */
+	THEME_COLOR_NORMAL,     /*!< Normal font color. */
+	THEME_COLOR_SELECTED,   /*!< Font color for selected elements. */
+	THEME_COLOR_SHADOW,     /*!< Shadow color. */
+	THEME_COLOR_LAST        /*!< Unused. */
+};
+
+/**
+ * \brief Abstract theme structure.
+ */
+struct theme {
+	/**
+	 * (+&) Fonts catalog.
+	 */
+	struct font *fonts[THEME_FONT_LAST];
+
+	/**
+	 * (+) Miscellaneous colors.
+	 */
+	unsigned long colors[THEME_COLOR_LAST];
+
+	/**
+	 * (+) Padding between GUI elements.
+	 */
+	unsigned int padding;
+
+	/**
+	 * (+) Draw a frame.
+	 *
+	 * This function is used to draw a box usually as a container where UI
+	 * elements will be put.
+	 *
+	 * \see \ref theme_draw_frame
+	 */
+	void (*draw_frame)(struct theme *, const struct frame *);
+
+	/**
+	 * (+) Draw a label.
+	 *
+	 * \see \ref theme_draw_label
+	 */
+	void (*draw_label)(struct theme *, const struct label *);
+
+	/**
+	 * (+) Draw a button.
+	 *
+	 * \see \ref theme_draw_button
+	 */
+	void (*draw_button)(struct theme *, const struct button *);
+
+	/**
+	 * (+) Draw a checkbox.
+	 *
+	 * \see \ref theme_draw_button
+	 */
+	void (*draw_checkbox)(struct theme *t, const struct checkbox *);
+};
+
+/**
+ * Initialize the theming system.
+ *
+ * \return false on errors
+ * \warning This function must be called before any other theme functions.
+ */
+bool
+theme_init(void);
+
+/**
+ * Get a reference to the default theme.
+ *
+ * \return A non-owning pointer to a static storage for the default theme
+ */
+struct theme *
+theme_default(void);
+
+/**
+ * Convenient shortcut to shallow copy src into dst.
+ *
+ * Use this function when you want your own local copy of a theme because you
+ * want to modify some attributes.
+ *
+ * This is a shortcut to `memcpy(dst, src, sizeof (*src))`.
+ *
+ * \pre dst != NULL
+ * \param dst the destination theme
+ * \param src the source theme (may be NULL)
+ * \note Resources are not cloned, internal pointers will adress the same
+ *       regions.
+ */
+void
+theme_shallow(struct theme *dst, const struct theme *src);
+
+/**
+ * Get the desired padding between GUI elements.
+ *
+ * \param t the theme to use (may be NULL)
+ * \return the padding in pixels
+ */
+unsigned int
+theme_padding(const struct theme *t);
+
+/**
+ * Draw a frame.
+ *
+ * \pre frame != NULL
+ * \param t the theme to use (may be NULL)
+ * \param frame the frame
+ */
+void
+theme_draw_frame(struct theme *t, const struct frame *frame);
+
+/**
+ * Draw a label.
+ *
+ * \pre label != NULL
+ * \param t the theme to use (may be NULL)
+ * \param label the label
+ */
+void
+theme_draw_label(struct theme *t, const struct label *label);
+
+/**
+ * Draw a button.
+ *
+ * \pre button != NULL
+ * \param t the theme to use (may be NULL)
+ * \param button the button
+ */
+void
+theme_draw_button(struct theme *t, const struct button *button);
+
+/**
+ * Draw a checkbox.
+ *
+ * \param t the theme to use (may be NULL)
+ * \param cb the checkbox
+ */
+void
+theme_draw_checkbox(struct theme *t, const struct checkbox *cb);
+
+/**
+ * Close associated resources.
+ */
+void
+theme_finish(void);
+
+#endif /* !MOLKO_THEME_H */