SDL: Implement inline text input (for MJ command)

Very few games use it (Mamorigami-sama and Les Chairs Cruelles), but
this could be reused when we add a pure SDL implementation of input
dialogs.

CMakeLists.txt

@@ -104,7 +104,7 @@ elseif (GTK2_FOUND)
     link_libraries(${Intl_LIBRARIES})
   endif()
 else()
-  set(SRC_MENU menu_null.c)
+  set(SRC_MENU menu_null.c sdl_input.c)
 endif()
 
 # Graphics

src/menu.h

@@ -26,7 +26,7 @@
 #include "portab.h"
 
 /* 文字列入力のパラメータ */
-typedef struct {
+typedef struct inputstring_param {
 	char *title;
 	char *oldstring;
 	const char *newstring;

src/menu_null.c

@@ -26,6 +26,7 @@
 
 #include "portab.h"
 #include "menu.h"
+#include "sdl_core.h"
 
 void menu_open(void) {
 	return;
@@ -41,8 +42,7 @@ boolean menu_inputstring(INPUTSTRING_PARAM *p) {
 }
 
 boolean menu_inputstring2(INPUTSTRING_PARAM *p) {
-	p->newstring = p->oldstring;
-	return TRUE;
+	return sdl_inputString(p);
 }
 
 boolean menu_inputnumber(INPUTNUM_PARAM *p) {

src/sdl_core.h

@@ -29,6 +29,8 @@
 #include "ags.h"
 #include "cursor.h"
 
+struct inputstring_param;
+
 /* 初期化関係 */
 extern int  sdl_Initilize(void);
 extern void sdl_Remove(void);
@@ -102,6 +104,7 @@ extern void sdl_mainIteration();
 extern boolean RawKeyInfo[];
 extern void sdl_sleep(int msec);
 extern void sdl_wait_vsync();
+extern boolean sdl_inputString(struct inputstring_param *);
 
 /* 初期化関係 */
 #define GraphicsInitilize() sdl_Initilize()

src/sdl_event.c

@@ -96,6 +96,10 @@ static void sdl_getEvent(void) {
 
 	while (SDL_PollEvent(&e)) {
 		had_input = true;
+
+		if (sdl_custom_event_handler && sdl_custom_event_handler(&e))
+			continue;
+
 		switch (e.type) {
 #ifndef __EMSCRIPTEN__
 		case SDL_QUIT:

src/sdl_input.c

@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2020 <KichikuouChrome@gmail.com>
+ *
+ * This program 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+*/
+#include "config.h"
+
+#include <string.h>
+#include <SDL.h>
+
+#include "sdl_core.h"
+#include "sdl_private.h"
+#include "menu.h"
+#include "nact.h"
+
+#define XMARGIN 3
+#define YMARGIN 2
+
+struct EditorState {
+	INPUTSTRING_PARAM *params;
+	SDL_Rect rect;
+	char *text;
+	char composingText[SDL_TEXTEDITINGEVENT_TEXT_SIZE];
+	int cursor;
+	boolean done;
+};
+static struct EditorState *input;
+
+static void redraw() {
+	const int bgcolor = nact->msg.WinBackgroundColor;
+	const int fgcolor = nact->msg.MsgFontColor;
+
+	ags_fillRectangle(input->rect.x, input->rect.y, input->rect.w, input->rect.h, bgcolor);
+
+	SDL_Rect r = {
+		.x = input->rect.x + XMARGIN,
+		.y = input->rect.y + YMARGIN,
+		.w = input->rect.w - XMARGIN * 2,
+		.h = input->rect.h - YMARGIN * 2,
+	};
+
+	if (*input->text) {
+		int w = sdl_drawString(r.x, r.y, input->text, fgcolor);
+		r.x += w;
+		r.w -= w;
+	}
+
+	if (*input->composingText) {
+		int w = sdl_drawString(r.x, r.y, input->composingText, fgcolor);
+		ags_fillRectangle(r.x, r.y + r.h, w, 2, fgcolor);  // underline
+	}
+
+	// FIXME: This doesn't work with propotional fonts!
+	int cursor_x = r.x + r.h * input->cursor;
+	ags_fillRectangle(cursor_x, r.y, 2, r.h, fgcolor);  // cursor
+
+	// Dib geometry -> window geometry
+	r.x -= nact->sys_view_area.x;
+	r.y -= nact->sys_view_area.y;
+	SDL_SetTextInputRect(&r);
+
+	ags_updateArea(input->rect.x, input->rect.y, input->rect.w, input->rect.h);
+}
+
+static boolean handle_event(const SDL_Event *e) {
+	switch (e->type) {
+	case SDL_KEYDOWN:
+		if (*input->composingText)
+			break;  // Let the IME handle this event.
+		switch (e->key.keysym.sym) {
+		case SDLK_RETURN:
+			input->params->newstring = input->text;
+			input->done = TRUE;
+			return TRUE;
+		case SDLK_ESCAPE:
+			input->params->newstring = NULL;
+			input->done = TRUE;
+			return TRUE;
+		case SDLK_BACKSPACE:
+			{
+				char *p = input->text + strlen(input->text) - 1;
+				while (p >= input->text && UTF8_TRAIL_BYTE(*p))
+					p--;
+				if (p >= input->text)
+					*p = '\0';
+				redraw();
+			}
+			return TRUE;
+		}
+		break;
+
+	case SDL_TEXTINPUT:
+		{
+			int chars = input->params->max;
+			for (const char *p = input->text; *p; p = advance_char(p, UTF8))
+				chars--;
+			const char *end = e->text.text;
+			while (chars > 0 && *end) {
+				end = advance_char(end, UTF8);
+				chars--;
+			}
+			strncat(input->text, e->text.text, end - e->text.text);
+
+			input->composingText[0] = '\0';
+			input->cursor = 0;
+			redraw();
+		}
+		return TRUE;
+
+	case SDL_TEXTEDITING:
+		strncpy(input->composingText, e->edit.text, SDL_TEXTEDITINGEVENT_TEXT_SIZE);
+		input->cursor = e->edit.start;
+		redraw();
+		return TRUE;
+	}
+	return FALSE;
+}
+
+boolean sdl_inputString(INPUTSTRING_PARAM *p) {
+	static char *buf;
+	free(buf);
+	buf = malloc(p->max * MAX_UTF8_BYTES_PAR_CHAR + 1);
+
+	struct EditorState s = {
+		.params = p,
+		.rect = {
+			.x = p->x + nact->sys_view_area.x,  // window geometry -> dib geometry
+			.y = p->y + nact->sys_view_area.y,
+			.w = p->h * p->max + XMARGIN * 2,
+			.h = p->h + YMARGIN * 2
+		},
+		.text = buf,
+	};
+	strcpy(s.text, p->oldstring);
+	input = &s;
+
+	SDL_StartTextInput();
+
+	void *saved_region = ags_saveRegion(s.rect.x, s.rect.y, s.rect.w, s.rect.h);
+	ags_setFont(FONT_GOTHIC, p->h);
+	redraw();
+
+	sdl_custom_event_handler = handle_event;
+	while (!input->done) {
+		sdl_getKeyInfo();  // message pump
+		nact->callback();
+		sdl_wait_vsync();
+	}
+	SDL_StopTextInput();
+	sdl_custom_event_handler = NULL;
+
+	ags_restoreRegion(saved_region, s.rect.x, s.rect.y);
+	ags_updateArea(s.rect.x, s.rect.y, s.rect.w, s.rect.h);
+
+	input = NULL;
+
+	return TRUE;
+}

src/sdl_private.h

@@ -59,6 +59,7 @@ struct sdl_private_data {
 	int      winoffset_x; /* draw offset in Window x */
 	int      winoffset_y; /*                       y */
 
+	boolean (*custom_event_handler)(const SDL_Event *);
 };
 
 extern void sdl_cursor_init(void);
@@ -88,6 +89,7 @@ extern struct sdl_private_data *sdl_videodev;
 #define sdl_fs_on (sdl_videodev->fs_on)
 #define winoffset_x (sdl_videodev->winoffset_x)
 #define winoffset_y (sdl_videodev->winoffset_y)
+#define sdl_custom_event_handler (sdl_videodev->custom_event_handler)
 
 #define setRect(r,xx,yy,ww,hh) (r).x=(xx),(r).y=(yy),(r).w=(ww),(r).h=(hh)
 #define setOffset(s,x,y) (s->pixels) + (x) * (s->format->BytesPerPixel) + (y) * s->pitch