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// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
const Lang = imports.lang;
const Clutter = imports.gi.Clutter;
function nextIndex(itemCount, numCols, currentIndex, symbol) {
let result = -1;
if (itemCount > 3 // grid navigation is not suited for a low item count
&& (symbol === Clutter.KEY_Down || symbol === Clutter.KEY_Up))
{
let numRows = Math.ceil(itemCount/numCols);
let curRow = Math.floor(currentIndex/numCols);
let curCol = currentIndex % numCols;
let numColsLastRow = itemCount % numCols || numCols;
let lastRowColStart = Math.floor((numCols - numColsLastRow) / 2);
if (symbol === Clutter.KEY_Down) {
if (curRow < numRows - 2) {
return (curRow + 1) * numCols + curCol;
}
if (curRow === numRows - 1) {
let actualCurCol = curCol + lastRowColStart;
return (actualCurCol < numCols - 1) ? actualCurCol + 1 : 0;
}
if (curCol >= lastRowColStart && curCol < lastRowColStart + numColsLastRow) {
return (curRow + 1) * numCols + curCol - lastRowColStart;
}
return (curCol < numCols - 1) ? curCol + 1 : 0;
}
else {
if (numRows === 1) {
return (curCol > 0) ? curCol - 1 : itemCount - 1;
}
if (curRow > 0 && curRow < numRows - 1) {
return (curRow - 1) * numCols + curCol;
}
if (curRow === numRows - 1) {
return (curRow - 1) * numCols + curCol + lastRowColStart;
}
if (curCol === 0) {
return (numColsLastRow === numCols) ? itemCount - 1 : (numRows - 1) * numCols - 1;
}
if (curCol >= lastRowColStart + 1 && curCol < lastRowColStart + numColsLastRow + 1) {
return (numRows - 1) * numCols + curCol - 1 - lastRowColStart;
}
return (numRows - 2) * numCols + curCol - 1;
}
}
else if (symbol === Clutter.KEY_Left || symbol === Clutter.KEY_Down) {
result = (currentIndex < 1 ? itemCount : currentIndex) - 1;
}
else if (symbol === Clutter.KEY_Right || symbol === Clutter.KEY_Up) {
result = (currentIndex + 1) % itemCount;
}
else if (symbol === Clutter.KEY_Home) {
result = 0;
}
else if (symbol === Clutter.KEY_End) {
result = itemCount - 1;
}
return result;
}
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