Add scrollable pane widget to textscreen library.

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 1437

1 files changed, 326 insertions, 0 deletions

diff --git a/textscreen/txt_scrollpane.c b/textscreen/txt_scrollpane.c
new file mode 100644
index 00000000..9049413b
--- /dev/null
+++ b/textscreen/txt_scrollpane.c
@@ -0,0 +1,326 @@
+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// Copyright(C) 2009 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.
+//
+// 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 <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"
+
+#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 = FullWidth(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;
+    }
+}
+
+static void TXT_ScrollPaneDrawer(TXT_UNCAST_ARG(scrollpane), int selected)
+{
+    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, selected);
+    }
+
+    // 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 int TXT_ScrollPaneKeyPress(TXT_UNCAST_ARG(scrollpane), int key)
+{
+    TXT_CAST_ARG(txt_scrollpane_t, scrollpane);
+
+    if (scrollpane->child != NULL)
+    {
+        return TXT_WidgetKeyPress(scrollpane->child, key);
+    }
+    else
+    {
+        return 0;
+    }
+}
+
+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);
+
+    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;
+        }
+
+        return;
+    }
+
+    // Click on the horizontal scrollbar?
+    if ((scrollbars & SCROLLBAR_VERTICAL) && rel_x == scrollpane->w)
+    {
+        if (rel_y == 0)
+        {
+            --scrollpane->y;
+        }
+        else if (rel_y == scrollpane->h - 1)
+        {
+            ++scrollpane->y;
+        }
+
+        return;
+    }
+
+    if (scrollpane->child != NULL)
+    {
+        TXT_WidgetMousePress(scrollpane->child,
+                             x - scrollpane->x,
+                             y - scrollpane->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_widget_class_t txt_scrollpane_class =
+{
+    TXT_ScrollPaneSizeCalc,
+    TXT_ScrollPaneDrawer,
+    TXT_ScrollPaneKeyPress,
+    TXT_ScrollPaneDestructor,
+    TXT_ScrollPaneMousePress,
+    TXT_ScrollPaneLayout,
+};
+
+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;
+
+    return scrollpane;
+}
+