From 48e6f641436ccdcb0395f3daa8dadb701bf821fa Mon Sep 17 00:00:00 2001
From: Alex Duchesne <alex@netvps.ca>
Date: Wed, 25 Jan 2023 16:44:25 -0500
Subject: [PATCH] Launcher: Added alternative scroll mode/behavior (#77)

---
 launcher/main/gui.c  | 23 ++++++++++++++++++-----
 launcher/main/gui.h  |  8 ++++++++
 launcher/main/main.c | 17 +++++++++++++++++
 3 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/launcher/main/gui.c b/launcher/main/gui.c
index 319083217..f1373dbdf 100644
--- a/launcher/main/gui.c
+++ b/launcher/main/gui.c
@@ -29,6 +29,7 @@ retro_gui_t gui;
 #define SETTING_THEME           "Theme"
 #define SETTING_COLOR_THEME     "ColorTheme"
 #define SETTING_SHOW_PREVIEW    "ShowPreview"
+#define SETTING_SCROLL_MODE     "ScrollMode"
 #define SETTING_HIDDEN_TABS     "HiddenTabs"
 #define SETTING_HIDE_TAB(name)  strcat((char[99]){"HideTab."}, (name))
 
@@ -48,6 +49,7 @@ void gui_init(void)
         .color_theme  = rg_settings_get_number(NS_APP, SETTING_COLOR_THEME, 0),
         .start_screen = rg_settings_get_number(NS_APP, SETTING_START_SCREEN, START_SCREEN_AUTO),
         .show_preview = rg_settings_get_number(NS_APP, SETTING_SHOW_PREVIEW, PREVIEW_MODE_SAVE_COVER),
+        .scroll_mode  = rg_settings_get_number(NS_APP, SETTING_SCROLL_MODE, SCROLL_MODE_CENTER),
         .width        = rg_display_get_info()->screen.width,
         .height       = rg_display_get_info()->screen.height,
     };
@@ -226,6 +228,7 @@ void gui_save_config(void)
     rg_settings_set_number(NS_APP, SETTING_SELECTED_TAB, gui.selected_tab);
     rg_settings_set_number(NS_APP, SETTING_START_SCREEN, gui.start_screen);
     rg_settings_set_number(NS_APP, SETTING_SHOW_PREVIEW, gui.show_preview);
+    rg_settings_set_number(NS_APP, SETTING_SCROLL_MODE, gui.scroll_mode);
     rg_settings_set_number(NS_APP, SETTING_COLOR_THEME, gui.color_theme);
     rg_settings_set_number(NS_APP, SETTING_STARTUP_MODE, gui.startup_mode);
     rg_settings_set_string(NS_APP, SETTING_HIDDEN_TABS, gui.hidden_tabs);
@@ -326,15 +329,15 @@ void gui_scroll_list(tab_t *tab, scroll_whence_t mode, int arg)
     }
     else if (mode == SCROLL_PAGE)
     {
-        int start = list->items[cur_cursor].text[0];
+        // int start = list->items[cur_cursor].text[0];
         int direction = arg > 0 ? 1 : -1;
-        for (int max = max_visible_lines(tab, NULL) - 2; max > 0; --max)
+        for (int max = max_visible_lines(tab, NULL); max > 0; --max)
         {
             cur_cursor += direction;
             if (cur_cursor < 0 || cur_cursor >= list->length)
                 break;
-            if (start != list->items[cur_cursor].text[0])
-                break;
+            // if (start != list->items[cur_cursor].text[0])
+            //     break;
         }
     }
 
@@ -448,6 +451,7 @@ void gui_draw_list(tab_t *tab)
     const listbox_t *list = &tab->listbox;
     int line_height, top = HEADER_HEIGHT + 6;
     int lines = max_visible_lines(tab, &line_height);
+    int line_offset = 0;
 
     if (tab->navpath)
     {
@@ -458,9 +462,18 @@ void gui_draw_list(tab_t *tab)
 
     top += ((gui.height - top) - (lines * line_height)) / 2;
 
+    if (gui.scroll_mode == SCROLL_MODE_PAGING)
+    {
+        line_offset = (list->cursor / lines) * lines;
+    }
+    else // (gui.scroll_mode == SCROLL_MODE_CENTER)
+    {
+        line_offset = list->cursor - (lines / 2);
+    }
+
     for (int i = 0; i < lines; i++)
     {
-        int idx = list->cursor + i - (lines / 2);
+        int idx = line_offset + i;
         int selected = idx == list->cursor;
         char *label = (idx >= 0 && idx < list->length) ? list->items[idx].text : "";
         top += rg_gui_draw_text(0, top, gui.width, label, fg[selected], bg[selected], 0).height;
diff --git a/launcher/main/gui.h b/launcher/main/gui.h
index 274aa6a37..5bad88a8f 100644
--- a/launcher/main/gui.h
+++ b/launcher/main/gui.h
@@ -10,6 +10,13 @@ typedef enum {
     START_SCREEN_COUNT,
 } start_screen_t;
 
+typedef enum {
+    SCROLL_MODE_CENTER,
+    SCROLL_MODE_PAGING,
+    // SCROLL_MODE_EDGE,
+    SCROLL_MODE_COUNT,
+} scroll_mode_t;
+
 typedef enum {
     TAB_ACTION,
     TAB_BACK,
@@ -117,6 +124,7 @@ typedef struct {
     int color_theme;
     int start_screen;
     int show_preview;
+    int scroll_mode;
     int width;
     int height;
     image_t images[128];
diff --git a/launcher/main/main.c b/launcher/main/main.c
index 92de7ccc2..1ed715be7 100644
--- a/launcher/main/main.c
+++ b/launcher/main/main.c
@@ -52,6 +52,22 @@ static rg_gui_event_t toggle_tabs_cb(rg_gui_option_t *option, rg_gui_event_t eve
     return RG_DIALOG_VOID;
 }
 
+static rg_gui_event_t scroll_mode_cb(rg_gui_option_t *option, rg_gui_event_t event)
+{
+    const char *modes[SCROLL_MODE_COUNT] = {"Center", "Paging"};
+    const int max = SCROLL_MODE_COUNT - 1;
+
+    if (event == RG_DIALOG_PREV && --gui.scroll_mode < 0)
+        gui.scroll_mode = max;
+    if (event == RG_DIALOG_NEXT && ++gui.scroll_mode > max)
+        gui.scroll_mode = 0;
+
+    gui.scroll_mode %= SCROLL_MODE_COUNT;
+
+    strcpy(option->value, modes[gui.scroll_mode]);
+    return RG_DIALOG_VOID;
+}
+
 static rg_gui_event_t timezone_cb(rg_gui_option_t *option, rg_gui_event_t event)
 {
     if (event == RG_DIALOG_ENTER)
@@ -153,6 +169,7 @@ static rg_gui_event_t launcher_options_cb(rg_gui_option_t *option, rg_gui_event_
     {
         const rg_gui_option_t options[] = {
             {0, "Color theme ", "...", 1, &color_theme_cb},
+            {0, "Scroll mode ", "...", 1, &scroll_mode_cb},
             {0, "Preview     ", "...", 1, &show_preview_cb},
             {0, "Start screen", "...", 1, &start_screen_cb},
             {0, "Hide tabs   ", "...", 1, &toggle_tabs_cb},