netsurf/desktop/textarea.h

/*
 * Copyright 2006 John-Mark Bell <jmb@netsurf-browser.org>
 * Copyright 2009 Paul Blokus <paul_pl@users.sourceforge.net> 
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/** \file
 * Single/Multi-line UTF-8 text area (interface)
 */

#ifndef _NETSURF_DESKTOP_TEXTAREA_H_
#define _NETSURF_DESKTOP_TEXTAREA_H_

#include <stdint.h>
#include <stdbool.h>

struct textarea;

/* Text area flags */
typedef enum {
	TEXTAREA_DEFAULT		= (1 << 0),	/**< Standard input */
	TEXTAREA_MULTILINE		= (1 << 1),	/**< Multiline area */
	TEXTAREA_READONLY		= (1 << 2),	/**< Non-editable */
	TEXTAREA_INTERNAL_CARET		= (1 << 3),	/**< Render own caret */
	TEXTAREA_PASSWORD		= (1 << 4)	/**< Obscured display */
} textarea_flags;

typedef enum {
	TEXTAREA_DRAG_NONE,
	TEXTAREA_DRAG_SCROLLBAR,
	TEXTAREA_DRAG_SELECTION
} textarea_drag_type;			/**< Textarea drag status */

typedef enum {
	TEXTAREA_MSG_DRAG_REPORT,	/**< Textarea drag start/end report */
	TEXTAREA_MSG_SELECTION_REPORT,	/**< Textarea text selection presence */
	TEXTAREA_MSG_REDRAW_REQUEST,	/**< Textarea redraw request */
	TEXTAREA_MSG_CARET_UPDATE,	/**< Textarea caret */
	TEXTAREA_MSG_TEXT_MODIFIED	/**< Textarea text modified */
} textarea_msg_type;

struct textarea_msg {
	struct textarea *ta;		/**< The textarea widget */

	textarea_msg_type type;		/**< Indicates message data type */
	union {
		textarea_drag_type drag;	/**< With _DRAG_REPORT */
		struct {
			bool have_selection;	/**< Selection exists */
			bool read_only;		/**< Selection can't be cut */
		} selection;			/**< With _SELECTION_REPORT */
		struct rect redraw;		/**< With _REDRAW_REQUEST */
		struct {
			enum {
				TEXTAREA_CARET_SET_POS,	/**< Set coord/height */
				TEXTAREA_CARET_HIDE	/**< Hide */
			} type;
			struct {
				int x;			/**< Carret x-coord */
				int y;			/**< Carret y-coord */
				int height;		/**< Carret height */
				struct rect *clip;	/**< Carret clip rect */
			} pos;			/**< With _CARET_SET_POS */
		} caret;			/**< With _CARET_UPDATE */
		struct {
			const char *text;	/**< UTF8 text */
			unsigned int len;	/**< Byte length of text */
		} modified;			/**< With _TEXT_MODIFIED */
	} data;				/**< Depends on msg type */
};

typedef struct textarea_setup {
	int width;		/**< Textarea width */
	int height;		/**< Textarea height */

	int pad_top;		/**< Textarea top padding */
	int pad_right;		/**< Textarea right padding */
	int pad_bottom;		/**< Textarea bottom padding */
	int pad_left;		/**< Textarea left padding */

	int border_width;	/**< Textarea border width */
	colour border_col;	/**< Textarea border colour */

	colour selected_text;	/**< Textarea selected text colour */
	colour selected_bg;	/**< Textarea selection background colour */
	plot_font_style_t text;	/**< Textarea background colour and font */

} textarea_setup;

/**
 * Client callback for the textarea
 *
 * \param data		user data passed at textarea creation
 * \param textarea_msg	textarea message data
 */
typedef void(*textarea_client_callback)(void *data, struct textarea_msg *msg);

/**
 * Create a text area
 *
 * \param setup	textarea settings and style
 * \param redraw_callback will be called when textarea wants to redraw
 * \param data	user specified data which will be passed to callbacks
 * \return Opaque handle for textarea or 0 on error
 */
struct textarea *textarea_create(const textarea_flags flags,
		const textarea_setup *setup,
		textarea_client_callback callback, void *data);

/**
 * Destroy a text area
 *
 * \param ta Text area to destroy
 */
void textarea_destroy(struct textarea *ta);

/**
 * Set the text in a text area, discarding any current text
 *
 * \param ta Text area
 * \param text UTF-8 text to set text area's contents to
 * \return true on success, false on memory exhaustion
 */
bool textarea_set_text(struct textarea *ta, const char *text);

/**
 * Insert the text in a text area at the caret, replacing any selection.
 *
 * \param ta Text area
 * \param text UTF-8 text to set text area's contents to
 * \return true on success, false on memory exhaustion or if ta lacks caret
 */
bool textarea_drop_text(struct textarea *ta, const char *text,
		size_t text_length);

/**
 * Extract the text from a text area
 *
 * \param ta Text area
 * \param buf Pointer to buffer to receive data, or NULL
 *            to read length required (includes trailing '\0')
 * \param len Length (bytes) of buffer pointed to by buf, or 0 to read length
 * \return Length (bytes) written/required or -1 on error
 */
int textarea_get_text(struct textarea *ta, char *buf, unsigned int len);

/**
 * Set the caret's position
 *
 * \param ta 		Text area
 * \param caret 	0-based character index to place caret at, -1 removes
 * 			the caret
 * \return true on success false otherwise
 */
bool textarea_set_caret(struct textarea *ta, int caret);

/**
 * Handle redraw requests for text areas
 *
 * \param ta	textarea to render
 * \param x	x coordinate of textarea top
 * \param y	y coordinate of textarea left
 * \param bg	background colour under textarea
 * \param scale scale to render at
 * \param clip	clip rectangle
 * \param ctx	current redraw context
 */
void textarea_redraw(struct textarea *ta, int x, int y, colour bg, float scale,
		const struct rect *clip, const struct redraw_context *ctx);

/**
 * Key press handling for text areas.
 *
 * \param ta	The text area which got the keypress
 * \param key	The ucs4 character codepoint
 * \return     	true if the keypress is dealt with, false otherwise.
 */
bool textarea_keypress(struct textarea *ta, uint32_t key);

/* Text area mouse input status flags */
typedef enum {
	TEXTAREA_MOUSE_NONE	= 0,		/**< Not relevant */
	TEXTAREA_MOUSE_USED	= (1 <<  0),	/**< Took action with input */
	TEXTAREA_MOUSE_EDITOR	= (1 <<  1),	/**< Hover: caret pointer */
	TEXTAREA_MOUSE_SELECTION= (1 <<  2),	/**< Hover: selection */
	TEXTAREA_MOUSE_SCR_USED	= (1 <<  3),	/**< Scrollbar action */
	TEXTAREA_MOUSE_SCR_BOTH	= (1 <<  4),	/**< Scrolling both bars */
	TEXTAREA_MOUSE_SCR_UP	= (1 <<  5),	/**< Hover: scroll up */
	TEXTAREA_MOUSE_SCR_PUP	= (1 <<  6),	/**< Hover: scroll page up */
	TEXTAREA_MOUSE_SCR_VRT	= (1 <<  7),	/**< Hover: vert. drag bar */
	TEXTAREA_MOUSE_SCR_PDWN	= (1 <<  8),	/**< Hover: scroll page down */
	TEXTAREA_MOUSE_SCR_DWN	= (1 <<  9),	/**< Hover: scroll down */
	TEXTAREA_MOUSE_SCR_LFT	= (1 << 10),	/**< Hover: scroll left */
	TEXTAREA_MOUSE_SCR_PLFT	= (1 << 11),	/**< Hover: scroll page left */
	TEXTAREA_MOUSE_SCR_HRZ	= (1 << 12),	/**< Hover: horiz. drag bar */
	TEXTAREA_MOUSE_SCR_PRGT	= (1 << 13),	/**< Hover: scroll page right */
	TEXTAREA_MOUSE_SCR_RGT	= (1 << 14)	/**< Hover: scroll right */
} textarea_mouse_status;

/**
 * Handles all kinds of mouse action
 *
 * \param ta	Text area
 * \param mouse	the mouse state at action moment
 * \param x	X coordinate
 * \param y	Y coordinate
 * \return the textarea mouse status
 */
textarea_mouse_status textarea_mouse_action(struct textarea *ta,
		browser_mouse_state mouse, int x, int y);

/**
 * Clear any selection in the textarea.
 *
 * \param ta	textarea widget
 * \return true if there was a selection to clear, false otherwise
 */
bool textarea_clear_selection(struct textarea *ta);

/**
 * Get selected text, ownership passed to caller, which needs to free() it.
 *
 * \param ta  Textarea widget
 * \return Selected text, or NULL if none.
 */
char *textarea_get_selection(struct textarea *ta);

/**
 * Gets the dimensions of a textarea
 *
 * \param ta		textarea widget
 * \param width		if not NULL, gets updated to the width of the textarea
 * \param height	if not NULL, gets updated to the height of the textarea
 */
void textarea_get_dimensions(struct textarea *ta, int *width, int *height);

/**
 * Set the dimensions of a textarea, causing a reflow and
 * Does not emit a redraw request.  Up to client to call textarea_redraw.
 *
 * \param ta		textarea widget
 * \param width 	the new width of the textarea
 * \param height	the new height of the textarea
 */
void textarea_set_dimensions(struct textarea *ta, int width, int height);

/**
 * Set the dimensions and padding of a textarea, causing a reflow.
 * Does not emit a redraw request.  Up to client to call textarea_redraw.
 *
 * \param ta		textarea widget
 * \param width 	the new width of the textarea
 * \param height	the new height of the textarea
 * \param top		the new top padding of the textarea
 * \param right		the new right padding of the textarea
 * \param bottom	the new bottom padding of the textarea
 * \param left		the new left padding of the textarea
 */
void textarea_set_layout(struct textarea *ta, int width, int height,
		int top, int right, int bottom, int left);

/**
 * Scroll a textarea by an amount.  Only does anything if multi-line textarea
 * has scrollbars.  If it scrolls, it will emit a redraw request.
 *
 * \param ta	textarea widget
 * \param scrx	number of px try to scroll in x direction
 * \param scry	number of px try to scroll in y direction
 * \return true iff the textarea was scrolled
 */
bool textarea_scroll(struct textarea *ta, int scrx, int scry);
#endif