# GridPainter ```csharp public sealed class GridPainter ``` Namespace `SharpCell.Grid` · package `SharpCell.Grid` Paints a worksheet the way Excel shows it: column and row headers, gridlines, each cell's `Cell.Text` in its style (font, fill, borders, alignment, wrapping, indent), merged areas as one cell, and the active cell. Only the cells inside the viewport are read, so a sheet's size does not matter. Also answers the geometry questions of a grid on screen: where a cell is, what is under a point, where to scroll. With [GridPainter.MeasureText](SharpCell.Grid.GridPainter.md#measuretext) set, text too wide for its cell runs on over empty neighbours, numbers too wide for their column are shortened or shown as `###`, and row headers widen for long row numbers, as in Excel. ## Constructors ### GridPainter() ```csharp public GridPainter() ``` A painter with Excel's default row heights and column widths. ### GridPainter(SheetLayout) ```csharp public GridPainter(SheetLayout layout) ``` A painter over the given sizes of rows and columns. ## Properties ### ColumnHeaderHeight ```csharp public double ColumnHeaderHeight { get; set; } ``` The height of the column headers at the top at 100% zoom; [GridPainter.Zoom](SharpCell.Grid.GridPainter.md#zoom) scales it. ### CopiedArea ```csharp public CellArea? CopiedArea { get; set; } ``` The cells copied or cut, painted with a dashed border as Excel shows them until they are pasted; null for none. ### FillArea ```csharp public CellArea? FillArea { get; set; } ``` The cells a fill handle is being dragged over, painted with a dashed grey border; null for none. ### FrozenColumns ```csharp public int FrozenColumns { get; set; } ``` How many columns on the left stay in place while the rest scrolls; a sheet's own is `Worksheet.FrozenColumns`. **Exceptions** - `ArgumentOutOfRangeException`: The count is negative or leaves no column to scroll. ### FrozenRows ```csharp public int FrozenRows { get; set; } ``` How many rows at the top stay in place while the rest scrolls, as Excel's Freeze Panes; a sheet's own is `Worksheet.FrozenRows`. **Exceptions** - `ArgumentOutOfRangeException`: The count is negative or leaves no row to scroll. ### Layout ```csharp public SheetLayout Layout { get; set; } ``` The sizes of rows and columns; [SheetLayout.FromWorksheet](SharpCell.Grid.SheetLayout.md#fromworksheet-worksheet-double) gives a sheet's own. ### MeasureText ```csharp public Func? MeasureText { get; set; } ``` The width in pixels of a line of text in a font. Without it, text is never fitted to its cell, row headers keep [GridPainter.RowHeaderWidth](SharpCell.Grid.GridPainter.md#rowheaderwidth), and Calibri 11's digit width is assumed. ### ReferenceArea ```csharp public CellArea? ReferenceArea { get; set; } ``` The cells picked with the mouse while a formula is typed, painted with a dashed blue border; null for none. ### RowHeaderWidth ```csharp public double RowHeaderWidth { get; set; } ``` The width of the row headers on the left at 100% zoom; with [GridPainter.MeasureText](SharpCell.Grid.GridPainter.md#measuretext), the least width, widened to fit the number of the last visible row. [GridPainter.Zoom](SharpCell.Grid.GridPainter.md#zoom) scales it. ### ShowsFillHandle ```csharp public bool ShowsFillHandle { get; set; } ``` Whether the selection's bottom-right corner has Excel's fill handle, the square dragged to fill cells. False by default; a view that changes cells turns it on. ### Theme ```csharp public GridTheme Theme { get; set; } ``` The colours of everything but the cells' own styles. ### Zoom ```csharp public double Zoom { get; set; } ``` How large cells and headers are painted, 1 for Excel's 100%: fonts, headers and the space around text grow with it, lines stay one pixel. [GridPainter.Layout](SharpCell.Grid.GridPainter.md#layout) is not scaled: give it the sheet's sizes at the zoom, as [SheetLayout.FromWorksheet](SharpCell.Grid.SheetLayout.md#fromworksheet-worksheet-double-double) with [GridPainter.MaxDigitWidth](SharpCell.Grid.GridPainter.md#maxdigitwidth-worksheet) does. **Exceptions** - `ArgumentOutOfRangeException`: The zoom is outside Excel's 10% to 400%. ## Methods ### CellBounds(GridViewport, CellPosition) ```csharp public GridRect CellBounds(GridViewport viewport, CellPosition cell) ``` Where a cell is on screen; it may lie outside the viewport. ### CellBounds(GridViewport, CellPosition, CellPosition) ```csharp public GridRect CellBounds(GridViewport viewport, CellPosition first, CellPosition last) ``` Where a rectangle of cells is on screen, from its top-left to its bottom-right cell. ### CellNearest(GridViewport, double, double) ```csharp public CellPosition CellNearest(GridViewport viewport, double x, double y) ``` The cell nearest to a point, for dragging a selection: the cell under it, or past an edge of the cells the next one out of view that way, so that scrolling to it follows the mouse. ### Clamp(GridViewport) ```csharp public GridViewport Clamp(GridViewport viewport) ``` The viewport with its offsets kept between the start and the end of the sheet. ### ColumnEdgeAt(GridViewport, double, double) ```csharp public int? ColumnEdgeAt(GridViewport viewport, double x, double y) ``` The column whose right edge is under a point of the column headers, as Excel lets it be dragged to resize the column; null elsewhere. Hidden columns are never found. ### FitColumnWidth(Worksheet, int) ```csharp public double? FitColumnWidth(Worksheet sheet, int column) ``` The width in pixels at [GridPainter.Zoom](SharpCell.Grid.GridPainter.md#zoom) that fits the widest text of a column, as Excel's AutoFit Column Width does; merged cells are left out. Null when the column holds nothing to fit or without [GridPainter.MeasureText](SharpCell.Grid.GridPainter.md#measuretext). ### FitRowHeight(Worksheet, int) ```csharp public double? FitRowHeight(Worksheet sheet, int row) ``` The height in pixels at [GridPainter.Zoom](SharpCell.Grid.GridPainter.md#zoom) that fits the tallest text of a row, as Excel's AutoFit Row Height does: a line of each cell's font, and as many lines as wrapped text or line breaks take. Null when the row holds nothing, for the sheet's default height. ### FontOf(CellFont) ```csharp public static GridFont FontOf(CellFont font) ``` The font of a SharpCell font at 96 DPI. ### Hit(GridViewport, double, double, Worksheet) ```csharp public GridHit? Hit(GridViewport viewport, double x, double y, Worksheet? sheet = null) ``` What is under a point of the grid: a cell, a column or row header, or the corner above the row headers; null outside the grid. [GridSelection.At](SharpCell.Grid.GridSelection.md#at-gridhit-worksheet) turns it into what a click selects. ### HitTest(GridViewport, double, double, Worksheet) ```csharp public CellPosition? HitTest(GridViewport viewport, double x, double y, Worksheet? sheet = null) ``` The cell under a point of the grid; null on the headers or outside the grid. Inside a merged area of the sheet, its top-left cell. ### IsOnFillHandle(GridViewport, double, double, GridSelection, Worksheet) ```csharp public bool IsOnFillHandle(GridViewport viewport, double x, double y, GridSelection? selection, Worksheet? sheet) ``` Whether a point is on the fill handle of the selection, when [GridPainter.ShowsFillHandle](SharpCell.Grid.GridPainter.md#showsfillhandle) shows one. ### MaxDigitWidth(Worksheet) ```csharp public double MaxDigitWidth(Worksheet? sheet) ``` The width in pixels of the widest digit of a sheet's default font at [GridPainter.Zoom](SharpCell.Grid.GridPainter.md#zoom), which Excel bases column widths on; 7, Calibri 11's at 100%, without [GridPainter.MeasureText](SharpCell.Grid.GridPainter.md#measuretext). ### Paint(IGridCanvas, Worksheet, GridViewport, CellPosition?) ```csharp public void Paint(IGridCanvas canvas, Worksheet? sheet, GridViewport viewport, CellPosition? activeCell = default) ``` Paints the part of the sheet in the viewport with the active cell alone selected; without a sheet, an empty grid. ### Paint(IGridCanvas, Worksheet, GridViewport, GridSelection) ```csharp public void Paint(IGridCanvas canvas, Worksheet? sheet, GridViewport viewport, GridSelection? selection) ``` Paints the part of the sheet in the viewport and the selection over it, as Excel does: the selected cells but the active one shaded, a border around them, their headers highlighted. Without a sheet, an empty grid; without a selection, none. ### RowEdgeAt(GridViewport, double, double) ```csharp public int? RowEdgeAt(GridViewport viewport, double x, double y) ``` The row whose bottom edge is under a point of the row headers; null elsewhere. See [GridPainter.ColumnEdgeAt](SharpCell.Grid.GridPainter.md#columnedgeat-gridviewport-double-double). ### ScrollIntoView(GridViewport, CellPosition) ```csharp public GridViewport ScrollIntoView(GridViewport viewport, CellPosition cell) ``` The viewport scrolled just enough to show the whole cell, or its top-left part when it is larger than the viewport; unchanged when the cell is already in view. ### VisibleArea(GridViewport) ```csharp public CellArea VisibleArea(GridViewport viewport) ``` The cells the viewport shows, partly or wholly, of the part that scrolls: frozen rows and columns aside.