Independent Scrollbar Control
Definition of independent scrollbar
Arrow, shaft and thumb are the components of scrollbar control. Some scrollbars don't have arrow, and some don't have shaft and thumb, as shown in Figure 1.
Figure 1 Scrollbar structure
Scrollbar is rectangular, it sends message to parent window when mouse clicks on it, and parent window will refresh the content of window and the position of thumb. It also sends message to parent window and do refresh when mouse clicks on arrow.
Types of Scrollbar
There are two kinds of scrollbar:
A part of main window or other controls, application specifies the scrollbar is horizontal or vertical by changing the style,
WS_HSCROLLorWS_VSCROLL. Main window or other controls can have both of these styles.Independent scrollbar, class name is
CTRL_SCROLLBAR. Application specifies the scrollbar is horizontal or vertical by selectingSBS_HORZorSBS_VERTwhen it is creating scrollbar control. It can only chose one of the styles.
The first one is not the topic of this chapter, but it is closely connected independent scrollbar, so we mentioned it.
Styles of Independent Scrollbar
Independent scrollbar has the following styles:
Table 1 The styles of independent scrollbar
Style Identifier
Meaning
SBS_HORZ
Create a horizontal scrollbar. The range of scrollbar is decided by the arguments (x, y, w, h) of CreateWindowEx2 when don't specify SBS_BOTTOMALIGN or SBS_TOPALIGN.
SBS_VERT
Create a vertical scrollbar. The range of scrollbar is decided by the arguments (x, y, w, h) of CreateWindowEx2 when don't specify SBS_LEFTALIGN or SBS_RIGHTALIGN.
SBS_BOTTOMALIGN
Be used with SBS_HORZ. Put horizontal scrollbar on the bottom of the range which is specified by CreateWindowEx2.
SBS_TOPALIGN
Be used with SBS_HORZ. Put horizontal scrollbar on the top of the range which is specified by CreateWindowEx2.
SBS_LEFTALIGN
Be used with SBS_VERT. Put vertical scrollbar on the left of the range which is specified by CreateWindowEx2.
SBS_RIGHTALIGN
Be used with SBS_VERT. Put vertical scrollbar on the right of the range which is specified by CreateWindowEx2.
SBS_NOARROWS
No arrow, can't be used with SBS_NOSHAFT
SBS_NOSHAFT
No shaft, can't be used with SBS_NOARROWS
SBS_FIXEDBARLEN
Thumb of horizontal or vertical scrollbar is fixed length
SBS_NOTNOTIFYPARENT
Send message to parent window, not notification code. It sends notification code in default
Messages of Independent Scrollbar
Application can send following messages to scrollbar control:
Get/set data information of scrollbar:
SBM_GETSCROLLINFO,SBM_SETSCROLLINFOGet /set current position of thumb:
SBM_GETPOS,SBM_SETPOSGet/set scroll range:
SBM_GETRANGE,SBM_SETRANGEGet/set scroll range and redraw immediately:
SBM_SETRANGEREDRAWEnable/disable arrow:
SBM_ENABLE_ARROW
Get Scrollbar Information
Application can get scrollbar's information (max/min value, pages of scrollbar and current position) by sending SBM_GETSCROLLINFO and wParam argument which is SCROLLINFO * pointer to scrollbar. The information is stored in the memory pointed by wParam.
/*
* Scroll bar information structure.
*/
typedef struct _SCROLLINFO
{
/** Size of the structrue in bytes */
UINT cbSize;
/**
* A flag indicates which fields contain valid values,
* can be OR'ed value of the following values:
* - SIF_RANGE\n
* Retrives or sets the range of the scroll bar.
* - SIF_PAGE\n
* Retrives or sets the page size of the scroll bar.
* - SIF_POS\n
* Retrives or sets the position of the scroll bar.
* - SIF_DISABLENOSCROLL\n
* Hides the scroll when disabled, not implemented so far.
*/
UINT fMask;
/** The minimum position value of the scroll bar */
int nMin;
/** The maximum position value of the scroll bar */
int nMax;
/** The page size of the scroll bar */
UINT nPage;
/** The position value of the scroll bar */
int nPos;
} SCROLLINFO, *PSCROLLINFO;The field fMask in SBM_GETSCROLLINFO structure specifies the information which can be got by sending SBM_GETSCROLLINFO message, fMask's value can be:
Table 2 The mask identifiers
| Information Identifier | Meaning | | SIF_RANGE | Get values range of scrollbar | | SIF_PAGE | Get the pages of scrollbar | | SIF_POS | Get scrollbar's current position | | SIF_ALL | Get all information |
The following codes can get all information of scrollbar
SCROLLINFO scinfo = {0};
scinfo.fMask = SIF_ALL;
SendMessage (hwnd_scrollbar, SBM_GETSCROLLINFO, (wParam)&scinfo, 0);Set Information of Scrollbar
We can send SBM_SETSCROLLINFO to scrollbar control to set information of scrollbar. wParam is a pointer of SCROLLINFO structure, it stores the scrollbar information which needs to be stored. IParam is used to determine to (TRUE) or not to (FALSE) redraw immediately.
The following sample is setting scrollbar's information and not redrawing immediately:
SCROLLINFO scinfo = {0};
scinfo.fMask = SIF_ALL;
scinfo.nMin = 0;
scinfo.nMax = 10;
scinfo.nPage = 2;
scinfo.nPos = 0;
BOOL redraw = FALSE;
SendMessage (hwnd_scrollbar, SBM_SETCROLLINFO, (wParam)&scinfo, redraw);Get Current Position of Thumb
We can send SBM_GETPOS message to scrollbar to get current position of thumb. Example is as follow:
int pos = SendMessage (hwnd_scrollbar, SBM_GETPOS, 0, 0);Set The Position of Thumb
We can send SBM_SETPOS message to scrollbar to set position of thumb. Target position is stored in wParam. IParam is used to determine to (TRUE) or not to (FALSE) redraw immediately.
int pos = 10;
SendMessage (hwnd_scrollbar, SBM_SETPOS, pos, TRUE);Get Scroll Range of Scrollbar
We can send SBM_GETRANGE message to get the scroll range of scrollbar. wParam stores min range and IParam stores max range.
int min, max;
SendMessage (hwnd_scrollbar, SBM_GETRANGE, &min, &max);Set Scroll Range of Scrollbar
We can send SBM_SETRANGE message to set the scroll range of scrollbar. wParam/IParam is min/max range to set. This message will not redraw scrollbar immediately.
The following codes set the scroll range of scroll bar from 0 to 100. But you can only see the change after other message or event redraws UI.
SendMessage (hwnd_scrollbar, SBM_SETRANGE, 0, 100);Set Scroll Range of Scrollbar and Redraw Immediately
We can send SBM_SETRANGEREDRAW message if we want to redraw scrollbar immediately after set the scroll range. wParam/IParam is min/max range to set.
The following codes set the scroll range of scroll bar from 0 to 100 and redraw immediately.
SendMessage (hwnd_scrollbar, SBM_SETRANGEREDRAW, 0, 100);Enable or Disable Arrow
Sending SBM_ENABLE_ARROW message can enable or disable arrow. Disable means the scrollbar can't scroll to the direction which is specified by disabled arrow. Arrow is enabled (disabled) when IParam is TRUE (FALSE). wParam's value is as follow:
Table 3 The arrow identifiers
Arrow Identifier
Meaning
SB_ARROW_LTUP
Left arrow key of horizontal scrollbar or up arrow key of vertical scrollbar
SB_ARROW_BTDN
Right arrow key of horizontal scrollbar or down arrow key of vertical scrollbar
SB_ARROW_BOTH
All arrow keys
The following codes disable all arrows of scrollbar:
SendMessage (hwnd_scrollbar, SBM_ENABLE_ARROW, SB_ARROW_BOTH, FALSE);Configurable Properties of Scrollbar
The following properties of scrollbar can be set by GetWindowElementAttr, SetWindowElementAttr, GetWindowElementPixelEx and SetWindowElementPixelEx functions in the following table.
Table 4 Notification codes table
| Property Identifier | Meaning | | WE_MAINC_THREED_BODY | Draw the colors of shaft and thumb | | WE_FGC_THREED_BODY | Draw the color of arrow | | WE_FGC_DISABLED_ITEM | Draw the color of disabled arrow | | WE_METRICS_SCROLLBAR | The size of scrollbar, that is, the height of horizontal scrollbar or the width of vertical scrollbar |
The following codes is an example for above properties:
DWORD color_3d, fgc_3d, fgc_dis;
gal_pixel old_brush_color;
//Get color value for each part of scrollbar
color_3d = GetWindowElementAttr(hWnd, WE_MAINC_THREED_BODY);
fgc_3d = GetWindowElementAttr(hWnd, WE_FGC_THREED_BODY);
fgc_dis = GetWindowElementAttr(hWnd, WE_FGC_DISABLED_ITEM);
//Draw shaft of scrollbar
old_brush_color = SetBrushColor(hdc,
RGBA2Pixel(hdc,GetRValue(color_3d),
GetGValue(color_3d), GetBValue(color_3d),
GetAValue(color_3d)));
FillBox(hdc, rect.left, rect.top, RECTW(rect), RECTH(rect));
SetBrushColor(hdc, old_brush_color);
//Draw arrow of scrollbar
draw_3dbox(hdc, &rect, color_3d,
bn_status | LFRDR_3DBOX_THICKFRAME | LFRDR_3DBOX_FILLED);
if(sb_status & SBS_DISABLED_LTUP || sb_status & SBS_DISABLED)
draw_arrow(hWnd, hdc, &rect, fgc_dis, LFRDR_ARROW_LEFT);
else
draw_arrow(hWnd, hdc, &rect, fgc_3d, LFRDR_ARROW_LEFT);Notification Codes of Scrollbar
All notification codes of scrollbar are in the following table:
Table 5 Notification codes table
Notification Code Identifier
Meaning
SB_LINEUP
Vertical scrollbar scrolls up one line
SB_LINEDOWN
Vertical scrollbar scrolls down one line
SB_PAGEUP
Vertical scrollbar scrolls up one page
SB_PAGEDOWN
Vertical scrollbar scrolls down one page
SB_LINELEFT
Horizontal scrollbar scrolls left one column
SB_LINERIGHT
Horizontal scrollbar scrolls right one column
SB_PAGELEFT
Horizontal scrollbar scrolls left one page
SB_PAGERIGHT
Horizontal scrollbar scrolls right one page
SB_THUMBPOSITION
Send the position of thumb to parent window by this notification code when mouse left button presses, drags and releases thumb
SB_THUMBTRACK
Keep sending the position of thumb to parent window by this notification code when mouse button is pressing and dragging the thumb
SB_TOP
Thumb arrives at left-most (top-most) of horizontal (vertical) scrollbar, that is, get the min value of scrollbar
SB_BOTTOM
Thumb arrives at right-most (bottom) of horizontal (vertical) scrollbar, that is, get the max value of scrollbar
After scrollbar specifies
SBS_NOTNOTIFYPARENTstyle, parent window of horizontal (vertical) scrollbar will receiveMSG_HSCROLL(MSG_VSCROLL) message.wParamis notification id,IParamis current position of thumb,curPos, when id isSB_THUMBPOSITIONorSB_THUMBTRACK. In other cases,IParamdoesn't have meaning.When scrollbar doesn't specify
SBS_NOTNOTIFYPARENTstyle, parent window of scrollbar will receive notification code.wParamincludes control ID and notification code. When notification code isSB_THUMBPOSITIONorSB_THUMBTRACK, parent window can get current position of thumb,curPos, by sendingSBM_GETPOS. Of course, the control doesn't sendMSG_COMMANDto parent window if you have invokedSetNotificationCallbackfunction to set callback function of scrollbar control, it invokes given callback function directly.
Trigger of Notification Message
Scrollbar can receive events of mouse and keyboard and trigger different notification message accroding to different situations.
It triggers different notification message when mouse clicks different part of scrollbar. It is important to note, when dragging thumb by using mouse left button, scrollbar keeps sending
SB_THUMBTRACKmessage, and it sendsSB_THUMBPOSITIONafter mouse left button is released. The messages which are triggered by the part of scrollbar are as follow:
Figure 2 notification messages which are triggered by mouse
The key of keyboard triggers corresponding notification message, see the following table:
Table 6 Notification Code table
Key
Notification Code
PAGEUP
Horizontal scrollbar sends SB_PAGELEFT; Vertical scrollbar sends SB_PAGEUP
PAGEDOWN
Horizontal scrollbar sends SB_PAGERIGHT ；Vertical scrollbar sends SB_PAGEDOWN
UpArrow
Vertical scrollbar sends SB_LINEUP
LeftArrow
Horizontal scrollbar sends SB_LINELEFT
DownArrow
Vertical scrollbar sends SB_LINEDOWN
RightArrow
Horizontal scrollbar sends SB_LINERIGHT
Sample Program
The following codes show how to create scrollbar with multiple styles. By operating mouse or keyboard, you can do many operations on scrollbar, for example, clicking, dragging and so on. To make the demo more vivid, we put a circle and a box on right of the window. The circle will become larger or smaller and the box will moved up or down, just follow scrollbar's control. Figure 3 is the screenshot, the codes are from scrollbar_ctrl.c in mg-samples, please see this file for full codes.
List 1 Scrollbar sample codes
#include <stdio.h>
#include <string.h>
#include <minigui/common.h>
#include <minigui/minigui.h>
#include <minigui/gdi.h>
#include <minigui/window.h>
#include <minigui/control.h>
#ifdef _LANG_ZHCN
#include "scrollbar_ctrl_res_cn.h"
#elif defined _LANG_ZHTW
#include "scrollbar_ctrl_res_tw.h"
#else
#include "scrollbar_ctrl_res_en.h"
#endif
/** define scrollbar data */
#define SB_MAX 20
#define SB_MIN 0
#define SB_PAGE 6
/** define circle data */
#define CC_CENTER_X 400
#define CC_CENTER_Y 100
#define CC_RADIUS_MAX 50
#define CC_RADIUS_MIN 0
/** define box data */
#define BOX_WIDTH 40
#define BOX_HEIGHT 20
#define BOX_Y_MAX 300
#define BOX_Y_MIN 200
/** x position of separator */
#define SEP 300
/** radius of circle */
int _radius;
/** y position of box */
int _box_pos_y;
/** invalidate rect */
RECT _rect_invalid;
static int ScrollbarProc(HWND hwnd, int message, WPARAM wParam, LPARAM lParam)
{
/** IDC of SCROLLBAR control */
static int _my_scroll_idc = 100;
/** scrollbar handle of main window */
static HWND hwnd_sb_main;
/** scrollbar handle of control */
HWND hwnd_sb_ctrl;
switch (message)
{
case MSG_CREATE:
{
_rect_invalid.left = SEP;
_rect_invalid.top = 0;
_rect_invalid.right = g_rcScr.right;
_rect_invalid.bottom = g_rcScr.bottom;
SCROLLINFO scinfo = {0};
scinfo.fMask = SIF_ALL;
scinfo.nMin = SB_MIN;
scinfo.nMax = SB_MAX;
scinfo.nPage = SB_PAGE;
scinfo.nPos = SB_MIN;
calc_circle_pos (scinfo.nPos);
calc_box_pos (scinfo.nPos);
/** classic VSCROLL with SBS_NOTNOTIFYPARENT */
hwnd_sb_main = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE |
SBS_VERT | SBS_LEFTALIGN
| SBS_NOTNOTIFYPARENT
,
0,
++_my_scroll_idc,
20, 50, 20, 150, hwnd,
"classic", 0,
0);
SendMessage (hwnd_sb_main, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_main, MSG_SETFOCUS, 0, 0);
/** flat VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE |
SBS_VERT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
43, 50, 20, 150, hwnd,
"flat", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** fashion VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE |
SBS_VERT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
66, 50, 20, 150, hwnd,
"fashion", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** tiny VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE |
SBS_VERT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
92, 50, 20, 150, hwnd,
"tiny", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** classic NOSHAFT VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOSHAFT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
120, 50, 20, 34, hwnd,
"classic", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** flat NOSHAFT VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOSHAFT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
140, 50, 20, 34, hwnd,
"flat", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** fashion NOSHAFT VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOSHAFT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
160, 50, 20, 34, hwnd,
"fashion", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** tiny NOSHAFT VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOSHAFT | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
184, 50, 20, 34, hwnd,
"tiny", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** classic NOARROW VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOARROW | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
210, 50, 20, 150, hwnd,
"classic", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** flat NOARROW VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOARROW | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
232, 50, 20, 150, hwnd,
"flat", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** fashion NOARROW VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOARROW | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
254, 50, 20, 150, hwnd,
"fashion", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** tiny NOARROW VSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_VERT | SBS_NOARROW | SBS_LEFTALIGN
,
0,
++_my_scroll_idc,
276, 50, 20, 150, hwnd,
"tiny", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** classic HSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_HORZ
| SBS_TOPALIGN
,
0,
++_my_scroll_idc,
20, 220, 150, 20, hwnd,
"classic", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** flat HSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_HORZ
| SBS_TOPALIGN
,
0,
++_my_scroll_idc,
20, 240, 150, 20, hwnd,
"flat", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** fashion HSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_HORZ
| SBS_TOPALIGN
,
0,
++_my_scroll_idc,
20, 260, 150, 20, hwnd,
"fashion", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
/** tiny HSCROLL */
hwnd_sb_ctrl = CreateWindowEx2 (CTRL_SCROLLBAR, "",
WS_VISIBLE | SBS_HORZ
| SBS_TOPALIGN
,
0,
++_my_scroll_idc,
20, 280, 150, 20, hwnd,
"tiny", 0,
0);
SendMessage (hwnd_sb_ctrl, SBM_SETSCROLLINFO, (WPARAM)&scinfo, TRUE);
SendMessage (hwnd_sb_ctrl, MSG_SETFOCUS, 0, 0);
}
break;
case MSG_COMMAND:
{
int code = HIWORD(wParam);
HWND scroll = (HWND)lParam;
int pos = 0;
switch (code)
{
case SB_LINELEFT:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
SendMessage (scroll, SBM_SETPOS, --pos, TRUE);
}
break;
case SB_LINERIGHT:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
SendMessage (scroll, SBM_SETPOS, ++pos, TRUE);
}
break;
case SB_PAGELEFT:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
pos -= SB_PAGE;
SendMessage (scroll, SBM_SETPOS, pos, TRUE);
}
break;
case SB_PAGERIGHT:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
pos += SB_PAGE;
SendMessage (scroll, SBM_SETPOS, pos, TRUE);
}
break;
case SB_LINEUP:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
SendMessage (scroll, SBM_SETPOS, --pos, TRUE);
}
break;
case SB_LINEDOWN:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
SendMessage (scroll, SBM_SETPOS, ++pos, TRUE);
}
break;
case SB_PAGEUP:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
pos -= SB_PAGE;
SendMessage (scroll, SBM_SETPOS, pos, TRUE);
}
break;
case SB_PAGEDOWN:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
pos += SB_PAGE;
SendMessage (scroll, SBM_SETPOS, pos, TRUE);
}
break;
case SB_THUMBPOSITION:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
}
break;
case SB_THUMBTRACK:
{
pos = SendMessage (scroll, SBM_GETPOS, 0, 0);
}
break;
case SB_TOP:
{
pos = SB_MIN;
}
break;
case SB_BOTTOM:
{
pos = SB_MAX;
}
break;
default:
break;
}
draw_shape (hwnd, pos);
}
break;
case MSG_HSCROLL:
{
int pos = 0;
switch (wParam)
{
case SB_LINELEFT:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
SendMessage (hwnd_sb_main, SBM_SETPOS, --pos, TRUE);
}
break;
case SB_LINERIGHT:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
SendMessage (hwnd_sb_main, SBM_SETPOS, ++pos, TRUE);
}
break;
case SB_PAGELEFT:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
pos -= SB_PAGE;
SendMessage (hwnd_sb_main, SBM_SETPOS, pos, TRUE);
}
break;
case SB_PAGERIGHT:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
pos += SB_PAGE;
SendMessage (hwnd_sb_main, SBM_SETPOS, pos, TRUE);
}
break;
case SB_THUMBPOSITION:
{
pos = (int)lParam;
}
break;
case SB_THUMBTRACK:
{
pos = (int)lParam;
}
break;
case SB_TOP:
{
pos = SB_MIN;
}
break;
case SB_BOTTOM:
{
pos = SB_MAX;
}
break;
default:
break;
}
draw_shape (hwnd, pos);
}
break;
case MSG_VSCROLL:
{
int pos = 0;
switch (wParam)
{
case SB_LINEUP:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
SendMessage (hwnd_sb_main, SBM_SETPOS, --pos, TRUE);
}
break;
case SB_LINEDOWN:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
SendMessage (hwnd_sb_main, SBM_SETPOS, ++pos, TRUE);
}
break;
case SB_PAGEUP:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
pos -= SB_PAGE;
SendMessage (hwnd_sb_main, SBM_SETPOS, pos, TRUE);
}
break;
case SB_PAGEDOWN:
{
pos = SendMessage (hwnd_sb_main, SBM_GETPOS, 0, 0);
pos += SB_PAGE;
SendMessage (hwnd_sb_main, SBM_SETPOS, pos, TRUE);
}
break;
case SB_THUMBPOSITION:
{
pos = (int)lParam;
}
break;
case SB_THUMBTRACK:
{
pos = (int)lParam;
}
break;
case SB_TOP:
{
pos = SB_MIN;
}
break;
case SB_BOTTOM:
{
pos = SB_MAX;
}
break;
default:
break;
}
draw_shape (hwnd, pos);
}
break;
case MSG_PAINT:
{
HDC hdc = BeginPaint(hwnd);
/** separator */
MoveTo (hdc, SEP, 0);
LineTo (hdc, SEP, g_rcScr.bottom);
/** circle */
Circle (hdc, CC_CENTER_X, CC_CENTER_Y, _radius);
/** top and bottom line of box */
MoveTo (hdc, SEP + 20, BOX_Y_MIN);
LineTo (hdc, SEP + 20 + BOX_WIDTH + 40, BOX_Y_MIN);
MoveTo (hdc, SEP + 20, BOX_Y_MAX);
LineTo (hdc, SEP + 20 + BOX_WIDTH + 40, BOX_Y_MAX);
/** box */
SetBrushColor (hdc, PIXEL_black);
FillBox (hdc, SEP + 40, _box_pos_y, BOX_WIDTH, BOX_HEIGHT);
EndPaint (hwnd, hdc);
}
break;
case MSG_CLOSE:
{
DestroyMainWindow (hwnd);
PostQuitMessage (hwnd);
return 0;
}
}
return DefaultMainWinProc(hwnd, message, wParam, lParam);
}
int MiniGUIMain (int argc, const char* argv[])
{
MSG Msg;
HWND hMainWnd;
MAINWINCREATE CreateInfo;
#ifdef _MGRM_PROCESSES
JoinLayer(NAME_DEF_LAYER , "scrollbar" , 0 , 0);
#endif
CreateInfo.dwStyle = WS_VISIBLE | WS_BORDER | WS_CAPTION;
CreateInfo.dwExStyle = WS_EX_NONE;
CreateInfo.spCaption = SCB_ST_CAP;
CreateInfo.hMenu = 0;
CreateInfo.hCursor = GetSystemCursor(0);
CreateInfo.hIcon = 0;
CreateInfo.MainWindowProc = ScrollbarProc;
CreateInfo.lx = 0;
CreateInfo.ty = 0;
CreateInfo.rx = g_rcScr.right;
CreateInfo.by = g_rcScr.bottom;
CreateInfo.iBkColor = COLOR_lightwhite;
CreateInfo.dwAddData = 0;
CreateInfo.hHosting = HWND_DESKTOP;
hMainWnd = CreateMainWindowEx (&CreateInfo, "flat", 0, 0, 0);
if (hMainWnd == HWND_INVALID)
{
return -1;
}
ShowWindow(hMainWnd, SW_SHOWNORMAL);
while (GetMessage(&Msg, hMainWnd)) {
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
MainWindowThreadCleanup (hMainWnd);
return 0;
}
#ifdef _MGRM_THREADS
#include <minigui/dti.c>
#endif
Figure 3 Scrollbar control
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