From b7d402cfbe5a26450f014ba1c219b90a29261f23 Mon Sep 17 00:00:00 2001
From: duncanspumpkin <duncans_pumpkin@hotmail.co.uk>
Date: Sun, 15 Nov 2015 13:55:09 +0000
Subject: [PATCH] Implement right click scrolling for scroll widgets.

Think this had just been missed. Its heavily modified from the original to match closer to what the rest of the code base does. Fixes #2052.
---
 src/input.c            | 85 ++++++++++++++++++++++++++++++++++++++++--
 src/interface/window.h |  1 +
 2 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/src/input.c b/src/input.c
index b8752736b9..6a8706a3e2 100644
--- a/src/input.c
+++ b/src/input.c
@@ -47,7 +47,7 @@
 static int _dragX, _dragY;
 static rct_windowclass _dragWindowClass;
 static rct_windownumber _dragWindowNumber;
-static int _dragWidgetIndex;
+static int _dragWidgetIndex, _dragScrollIndex;
 static int _originalWindowWidth, _originalWindowHeight;
 
 typedef struct {
@@ -180,6 +180,83 @@ static rct_mouse_data* get_mouse_input()
 	return &mouse_buffer[read_index];
 }
 
+/* rct2: 0x006E957F
+ */
+static void input_scroll_drag_begin(int x, int y, rct_window* w, rct_widget* widget, int widgetIndex) {
+	RCT2_GLOBAL(RCT2_ADDRESS_INPUT_STATE, uint8) = INPUT_STATE_SCROLL_RIGHT;
+	_dragX = x;
+	_dragY = y;
+	_dragWindowClass = w->classification;
+	_dragWindowNumber = w->number;
+	_dragWidgetIndex = widgetIndex;
+	RCT2_GLOBAL(RCT2_ADDRESS_TICKS_SINCE_DRAG_START, sint16) = 0;
+
+	_dragScrollIndex = window_get_scroll_data_index(w, widgetIndex);
+	platform_hide_cursor();
+}
+
+/* Based on (heavily changed) rct2: 0x006E9E0E & 0x006E9ED0 */
+static void input_scroll_drag_continue(int x, int y, rct_window* w) {
+	uint8 widgetIndex = _dragWidgetIndex;
+	uint8 scrollIndex = _dragScrollIndex;
+
+	rct_widget* widget = &w->widgets[widgetIndex];
+	rct_scroll* scroll = &w->scrolls[scrollIndex];
+
+	int dx, dy;
+	dx = x - _dragX;
+	dy = y - _dragY;
+
+	if (scroll->flags & HSCROLLBAR_VISIBLE) {
+		sint16 size = widget->right - widget->left - 1;
+		if (scroll->flags & VSCROLLBAR_VISIBLE)
+			size -= 11;
+		size = max(0, scroll->h_right - size);
+		scroll->h_left = min(max(0, scroll->h_left + dx), size);
+	}
+
+	if (scroll->flags & VSCROLLBAR_VISIBLE) {
+		sint16 	size = widget->bottom - widget->top - 1;
+		if (scroll->flags & HSCROLLBAR_VISIBLE)
+			size -= 11;
+		size = max(0, scroll->v_bottom - size);
+		scroll->v_top = min(max(0, scroll->v_top + dy), size);
+	}
+
+	widget_scroll_update_thumbs(w, widgetIndex);
+	window_invalidate_by_number(w->classification, w->number);
+	platform_set_cursor_position(_dragX, _dragY);
+}
+
+/* rct2: 0x006E8ACB*/
+static void input_scroll_right(int x, int y, int state) {
+	rct_window* w = window_find_by_number(
+		_dragWindowClass,
+		_dragWindowNumber
+		);
+	
+	if (w == NULL) {
+		platform_show_cursor();
+		RCT2_GLOBAL(RCT2_ADDRESS_INPUT_STATE, uint8) = INPUT_STATE_RESET;
+		return;
+	}
+
+	switch (state) {
+	case 0:
+		RCT2_GLOBAL(RCT2_ADDRESS_TICKS_SINCE_DRAG_START, sint16) += RCT2_GLOBAL(RCT2_ADDRESS_TICKS_SINCE_LAST_UPDATE, sint16);
+		if (x == 0 && y == 0)
+			return;
+		RCT2_GLOBAL(RCT2_ADDRESS_TICKS_SINCE_DRAG_START, sint16) = 1000;
+
+		input_scroll_drag_continue(x, y, w);
+		break;
+	case 4:
+		RCT2_GLOBAL(RCT2_ADDRESS_INPUT_STATE, uint8) = INPUT_STATE_RESET;
+		platform_show_cursor();
+		break;
+	}
+}
+
 /**
  *
  *  rct2: 0x006E8655
@@ -221,7 +298,7 @@ static void game_handle_input_mouse(int x, int y, int state)
 					input_viewport_drag_begin(w, x, y);
 			}
 			else if (widget->type == WWT_SCROLL) {
-
+				input_scroll_drag_begin(x, y, w, widget, widgetIndex);
 			}
 			break;
 		}
@@ -325,8 +402,8 @@ static void game_handle_input_mouse(int x, int y, int state)
 				input_window_resize_continue(w, x, y);
 		}
 		break;
-	case 9:
-		RCT2_CALLPROC_X(0x006E8ACB, x, y, state, widgetIndex, (int)w, (int)widget, 0);
+	case INPUT_STATE_SCROLL_RIGHT:
+		input_scroll_right(x, y, state);
 		break;
 	}
 }
diff --git a/src/interface/window.h b/src/interface/window.h
index 2bc6786893..28862b35c9 100644
--- a/src/interface/window.h
+++ b/src/interface/window.h
@@ -382,6 +382,7 @@ enum {
 	INPUT_STATE_VIEWPORT_LEFT = 6,
 	INPUT_STATE_SCROLL_LEFT = 7,
 	INPUT_STATE_RESIZING = 8,
+	INPUT_STATE_SCROLL_RIGHT = 9
 };
 
 enum {