[Gammix]

posY - this will store your textdraw Y position
height - this will be your textdraw height (TextSize)
startY - put in your default position of scrollbar (where the scroll bar starts from)
maxHeight - maximum height the scollbar can have, expand your scrollbar to max and note the TextSize of Y
totalItems - how many items are there in your list
pageSize - how many items a page can display
currentPage - by default your scrollbar will start from 0, you can set this to whatever page you wish to start from

PHP код:

stock ScrollBar(&Float:posY, &Float:height, Float:startY, Float:maxHeight, totalItems, pageSize, currentPage = 0) {
    // calculate how many pages can be possible
    new pages = (totalItems / pageSize) + ((totalItems % pageSize) ? 1 : 0);
    // scrollbar height (Y-axis)
    height = (maxHeight / pages);
    
    // scrollbar position (Y-axis)
    // the position adjust with the page number you set in "currentPage" (0 = startY)
    posY = startY;
    posY += (height * currentPage);
} 


Note: Use font type 4 for making scrollbar textdraw, the algorithm works perfectly for it. Recommended to use "LD_SPAC:WHITE" or "LD_SPAC:BLACK" sprites.

Example usage: (why not)

PHP код:

new PlayerText:scrollPTD[MAX_PLAYERS];
public OnPlayerConnect(playerid) {
    new Float:y, Float:height;
    ScrollBar(y, height, 166.5, 108.0, 100, 10); // 100 items and each page handles 10 items
    
    scrollPTD[playerid] = CreatePlayerTextDraw(playerid, 489.0000, y, "LD_SPAC:WHITE");
    PlayerTextDrawFont(playerid, scrollPTD[playerid], 4);
    PlayerTextDrawLetterSize(playerid, scrollPTD[playerid], 0.0000, 18.2000);
    PlayerTextDrawColor(playerid, scrollPTD[playerid], -16776961);
    PlayerTextDrawSetShadow(playerid, scrollPTD[playerid], 0);
    PlayerTextDrawSetOutline(playerid, scrollPTD[playerid], 0);
    PlayerTextDrawBackgroundColor(playerid, scrollPTD[playerid], 255);
    PlayerTextDrawSetProportional(playerid, scrollPTD[playerid], 1);
    PlayerTextDrawUseBox(playerid, scrollPTD[playerid], 1);
    PlayerTextDrawBoxColor(playerid, scrollPTD[playerid], 150);
    PlayerTextDrawTextSize(playerid, scrollPTD[playerid], 7.5000, height);
    PlayerTextDrawShow(playerid, scrollPTD[playerid]);
}