ref: 78886030b9a08a39f46e0e53b64194b59813f21c
dir: /textscreen/txt_scrollpane.c/
//
// Copyright(C) 2005-2014 Simon Howard
//
// 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.
//
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "txt_scrollpane.h"
#include "txt_gui.h"
#include "txt_io.h"
#include "txt_main.h"
#include "txt_table.h"
#include "doomkeys.h"
#define SCROLLBAR_VERTICAL (1 << 0)
#define SCROLLBAR_HORIZONTAL (1 << 1)
static int FullWidth(txt_scrollpane_t *scrollpane)
{
if (scrollpane->child != NULL)
{
return scrollpane->child->w;
}
else
{
return 0;
}
}
static int FullHeight(txt_scrollpane_t *scrollpane)
{
if (scrollpane->child != NULL)
{
return scrollpane->child->h;
}
else
{
return 0;
}
}
// Calculate which scroll bars the pane needs.
static int NeedsScrollbars(txt_scrollpane_t *scrollpane)
{
int result;
result = 0;
if (FullWidth(scrollpane) > scrollpane->w)
{
result |= SCROLLBAR_HORIZONTAL;
}
if (FullHeight(scrollpane) > scrollpane->h)
{
result |= SCROLLBAR_VERTICAL;
}
return result;
}
// If a scrollbar isn't needed, the scroll position is reset.
static void SanityCheckScrollbars(txt_scrollpane_t *scrollpane)
{
int scrollbars;
int max_x, max_y;
scrollbars = NeedsScrollbars(scrollpane);
if ((scrollbars & SCROLLBAR_HORIZONTAL) == 0)
{
scrollpane->x = 0;
}
if ((scrollbars & SCROLLBAR_VERTICAL) == 0)
{
scrollpane->y = 0;
}
max_x = FullWidth(scrollpane) - scrollpane->w;
max_y = FullHeight(scrollpane) - scrollpane->h;
if (scrollpane->x < 0)
{
scrollpane->x = 0;
}
else if (scrollpane->x > max_x)
{
scrollpane->x = max_x;
}
if (scrollpane->y < 0)
{
scrollpane->y = 0;
}
else if (scrollpane->y > max_y)
{
scrollpane->y = max_y;
}
}
static void TXT_ScrollPaneSizeCalc(TXT_UNCAST_ARG(scrollpane))
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
int scrollbars;
if (scrollpane->child != NULL)
{
TXT_CalcWidgetSize(scrollpane->child);
}
// Expand as necessary (to ensure that no scrollbars are needed)?
if (scrollpane->expand_w)
{
scrollpane->w = FullWidth(scrollpane);
}
if (scrollpane->expand_h)
{
scrollpane->h = FullHeight(scrollpane);
}
scrollpane->widget.w = scrollpane->w;
scrollpane->widget.h = scrollpane->h;
// If we have scroll bars, we need to expand slightly to
// accomodate them. Eg. if we have a vertical scrollbar, we
// need to be an extra character wide.
scrollbars = NeedsScrollbars(scrollpane);
if (scrollbars & SCROLLBAR_HORIZONTAL)
{
++scrollpane->widget.h;
}
if (scrollbars & SCROLLBAR_VERTICAL)
{
++scrollpane->widget.w;
}
if (scrollpane->child != NULL)
{
if (scrollpane->child->w < scrollpane->w)
{
scrollpane->child->w = scrollpane->w;
}
if (scrollpane->child->h < scrollpane->h)
{
scrollpane->child->h = scrollpane->h;
}
}
}
static void TXT_ScrollPaneDrawer(TXT_UNCAST_ARG(scrollpane))
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
int x1, y1, x2, y2;
int scrollbars;
// We set a clipping area of the scroll pane.
x1 = scrollpane->widget.x,
y1 = scrollpane->widget.y,
x2 = x1 + scrollpane->w,
y2 = y1 + scrollpane->h;
scrollbars = NeedsScrollbars(scrollpane);
if (scrollbars & SCROLLBAR_HORIZONTAL)
{
TXT_DrawHorizScrollbar(x1,
y1 + scrollpane->h,
scrollpane->w,
scrollpane->x,
FullWidth(scrollpane) - scrollpane->w);
}
if (scrollbars & SCROLLBAR_VERTICAL)
{
TXT_DrawVertScrollbar(x1 + scrollpane->w,
y1,
scrollpane->h,
scrollpane->y,
FullHeight(scrollpane) - scrollpane->h);
}
TXT_PushClipArea(x1, x2, y1, y2);
// Draw the child widget
if (scrollpane->child != NULL)
{
TXT_DrawWidget(scrollpane->child);
}
// Restore old clipping area.
TXT_PopClipArea();
}
static void TXT_ScrollPaneDestructor(TXT_UNCAST_ARG(scrollpane))
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
if (scrollpane->child != NULL)
{
TXT_DestroyWidget(scrollpane->child);
}
}
static void TXT_ScrollPaneFocused(TXT_UNCAST_ARG(scrollpane), int focused)
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
// Whether the child is focused depends only on whether the scroll pane
// itself is focused. Pass through focus to the child.
if (scrollpane->child != NULL)
{
TXT_SetWidgetFocus(scrollpane->child, focused);
}
}
// Hack for tables - when browsing a table inside a scroll pane,
// automatically scroll the window to show the newly-selected
// item.
static void ShowSelectedWidget(txt_scrollpane_t *scrollpane)
{
txt_widget_t *selected;
selected = TXT_GetSelectedWidget(scrollpane->child);
// Scroll up or down?
if (selected->y <= scrollpane->widget.y)
{
scrollpane->y -= scrollpane->widget.y - selected->y;
}
else if ((signed) (selected->y + selected->h) >
(signed) (scrollpane->widget.y + scrollpane->h))
{
scrollpane->y += (selected->y + selected->h)
- (scrollpane->widget.y + scrollpane->h);
}
// Scroll left or right?
if (selected->x <= scrollpane->widget.x)
{
scrollpane->x -= scrollpane->widget.x - selected->x;
}
else if ((signed) (selected->x + selected->w) >
(signed) (scrollpane->widget.x + scrollpane->w))
{
scrollpane->x += (selected->x + selected->w)
- (scrollpane->widget.x + scrollpane->w);
}
}
// Another hack for tables - when scrolling in 'pages', the normal key press
// event does not provide children with enough information to know how far
// to move their selection to reach a new page. This function does so.
// Note that it *only* affects scrolling in pages, not with arrows!
// A side-effect of this, rather than 'pulling' the selection to fit within
// the new page, is that we will jump straight over ranges of unselectable
// items longer than a page, but that is also true of arrow-key scrolling.
// The other unfortunate effect of doing things this way is that page keys
// have no effect on tables _not_ in scrollpanes: not even home/end.
static int PageSelectedWidget(txt_scrollpane_t *scrollpane, int key)
{
int pagex = 0; // No page left/right yet, but some keyboards have them
int pagey = 0;
// Subtract one from the absolute page distance as this is slightly more
// intuitive: a page down first jumps to the bottom of the current page,
// then proceeds to scroll onwards.
switch (key)
{
case KEY_PGUP:
pagey = 1 - scrollpane->h;
break;
case KEY_PGDN:
pagey = scrollpane->h - 1;
break;
default: // We shouldn't even be in this function
return 0;
}
if (scrollpane->child->widget_class == &txt_table_class)
{
return TXT_PageTable(scrollpane->child, pagex, pagey);
}
return 0;
}
// Interpret arrow key presses as scroll commands
static int InterpretScrollKey(txt_scrollpane_t *scrollpane, int key)
{
int maxy;
switch (key)
{
case KEY_UPARROW:
if (scrollpane->y > 0)
{
--scrollpane->y;
return 1;
}
break;
case KEY_DOWNARROW:
if (scrollpane->y < FullHeight(scrollpane) - scrollpane->h)
{
++scrollpane->y;
return 1;
}
break;
case KEY_LEFTARROW:
if (scrollpane->x > 0)
{
--scrollpane->x;
return 1;
}
break;
case KEY_RIGHTARROW:
if (scrollpane->x < FullWidth(scrollpane) - scrollpane->w)
{
++scrollpane->x;
return 1;
}
break;
case KEY_PGUP:
if (scrollpane->y > 0)
{
scrollpane->y -= scrollpane->h;
if (scrollpane->y < 0)
{
scrollpane->y = 0;
}
return 1;
}
break;
case KEY_PGDN:
maxy = FullHeight(scrollpane) - scrollpane->h;
if (scrollpane->y < maxy)
{
scrollpane->y += scrollpane->h;
if (scrollpane->y > maxy)
{
scrollpane->y = maxy;
}
return 1;
}
break;
default:
break;
}
return 0;
}
static int TXT_ScrollPaneKeyPress(TXT_UNCAST_ARG(scrollpane), int key)
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
int result;
result = 0;
if (scrollpane->child != NULL)
{
result = TXT_WidgetKeyPress(scrollpane->child, key);
// Gross hack - if we're scrolling in a menu with the keyboard,
// automatically move the scroll pane to show the new
// selected item.
if ((key == KEY_UPARROW || key == KEY_DOWNARROW
|| key == KEY_LEFTARROW || key == KEY_RIGHTARROW
|| key == KEY_PGUP || key == KEY_PGDN
|| key == KEY_TAB)
&& scrollpane->child->widget_class == &txt_table_class)
{
if (PageSelectedWidget(scrollpane, key))
{
result = 1;
}
ShowSelectedWidget(scrollpane);
}
// If the child widget didn't use the keypress, we can see
// if it can be interpreted as a scrolling command.
if (result == 0)
{
result = InterpretScrollKey(scrollpane, key);
}
}
return result;
}
static void TXT_ScrollPaneMousePress(TXT_UNCAST_ARG(scrollpane),
int x, int y, int b)
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
int scrollbars;
int rel_x, rel_y;
scrollbars = NeedsScrollbars(scrollpane);
if (b == TXT_MOUSE_SCROLLUP)
{
if (scrollbars & SCROLLBAR_VERTICAL)
{
scrollpane->y -= 3;
}
else if (scrollbars & SCROLLBAR_HORIZONTAL)
{
scrollpane->x -= 3;
}
return;
}
else if (b == TXT_MOUSE_SCROLLDOWN)
{
if (scrollbars & SCROLLBAR_VERTICAL)
{
scrollpane->y += 3;
}
else if (scrollbars & SCROLLBAR_HORIZONTAL)
{
scrollpane->x += 3;
}
return;
}
rel_x = x - scrollpane->widget.x;
rel_y = y - scrollpane->widget.y;
// Click on the horizontal scrollbar?
if ((scrollbars & SCROLLBAR_HORIZONTAL) && rel_y == scrollpane->h)
{
if (rel_x == 0)
{
--scrollpane->x;
}
else if (rel_x == scrollpane->w - 1)
{
++scrollpane->x;
}
else
{
int range = FullWidth(scrollpane) - scrollpane->w;
int bar_max = scrollpane->w - 3;
scrollpane->x = ((rel_x - 1) * range + bar_max - 1) / bar_max;
}
return;
}
// Click on the vertical scrollbar?
if ((scrollbars & SCROLLBAR_VERTICAL) && rel_x == scrollpane->w)
{
if (rel_y == 0)
{
--scrollpane->y;
}
else if (rel_y == scrollpane->h - 1)
{
++scrollpane->y;
}
else
{
int range = FullHeight(scrollpane) - scrollpane->h;
int bar_max = scrollpane->h - 3;
scrollpane->y = ((rel_y - 1) * range + bar_max - 1) / bar_max;
}
return;
}
if (scrollpane->child != NULL)
{
TXT_WidgetMousePress(scrollpane->child, x, y, b);
}
}
static void TXT_ScrollPaneLayout(TXT_UNCAST_ARG(scrollpane))
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
SanityCheckScrollbars(scrollpane);
// The child widget takes the same position as the scroll pane
// itself, but is offset by the scroll position.
if (scrollpane->child != NULL)
{
scrollpane->child->x = scrollpane->widget.x - scrollpane->x;
scrollpane->child->y = scrollpane->widget.y - scrollpane->y;
TXT_LayoutWidget(scrollpane->child);
}
}
static int TXT_ScrollPaneSelectable(TXT_UNCAST_ARG(scrollpane))
{
TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
// If scroll bars are displayed, the scroll pane must be selectable
// so that we can use the arrow keys to scroll around.
if (NeedsScrollbars(scrollpane))
{
return 1;
}
// Otherwise, whether this is selectable depends on the child widget.
return TXT_SelectableWidget(scrollpane->child);
}
txt_widget_class_t txt_scrollpane_class =
{
TXT_ScrollPaneSelectable,
TXT_ScrollPaneSizeCalc,
TXT_ScrollPaneDrawer,
TXT_ScrollPaneKeyPress,
TXT_ScrollPaneDestructor,
TXT_ScrollPaneMousePress,
TXT_ScrollPaneLayout,
TXT_ScrollPaneFocused,
};
txt_scrollpane_t *TXT_NewScrollPane(int w, int h, TXT_UNCAST_ARG(target))
{
TXT_CAST_ARG(txt_widget_t, target);
txt_scrollpane_t *scrollpane;
scrollpane = malloc(sizeof(txt_scrollpane_t));
TXT_InitWidget(scrollpane, &txt_scrollpane_class);
scrollpane->w = w;
scrollpane->h = h;
scrollpane->x = 0;
scrollpane->y = 0;
scrollpane->child = target;
scrollpane->expand_w = w <= 0;
scrollpane->expand_h = h <= 0;
// Set parent pointer for inner widget.
target->parent = &scrollpane->widget;
return scrollpane;
}