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Prima::Grids

grid widgets

The module provides classes for several abstraction layers of grid representation. The classes hierarchy is as follows:

        AbstractGridViewer
                AbstractGrid
                GridViewer
                        Grid

The root class, "Prima::AbstractGridViewer", provides common interface, while by itself it is not directly usable. The main differences between classes are centered around the way the cell data are stored. The simplest organization of a text-only cell, provided by "Prima::Grid", stores data as a two-dimensional array of text scalars. More elaborated storage and representation types are not realized, and the programmer is urged to use the more abstract classes to derive own mechanisms. To organize an item storage, different from "Prima::Grid", it is usually enough to overload either the "Stringify", "Measure", and "DrawCell" events, or their method counterparts: "get_cell_text", "columnWidth", "rowHeight", and "draw_items".

The grid widget is designed to contain cells of variable extents, of two types, normal and indent. The indent rows and columns are displayed in grid margins, and their cell are drawn with distinguished colors. An example use for a bottom indent row is a sum row in a spreadsheet application; the top indent row can be used for displaying columns' headers. The normal cells can be selected by the user, scrolled, and selected. The cell selection can only contain rectangular areas, and therefore is operated with two integer pairs with the beginning and the end of the selection.

The widget operates in two visual scrolling modes; when the space allows, the scrollbars affect the leftmost and the topmost cell. When the widget is not large enough to accommodate at least one cell and all indent cells, the layout is scrolled pixel-wise. These modes are named 'cell' and 'pixel', after the scrolling units.

The widget allows the interactive changing of cell widths and heights by dragging the grid lines between the cells.

"Prima::AbstractGridViewer", the base for all grid widgets in the module, provides interface to generic grid browsing functionality, plus functionality for text-oriented grids. The class is not usable directly.

"Prima::AbstractGridViewer" is a descendant of "Prima::GroupScroller", and some properties are not described here. See "Prima::GroupScroller" in Prima::IntUtils.

allowChangeCellHeight BOOLEAN
If 1, the user is allowed to change vertical extents of cells by dragging the horizontal grid lines. Prerequisites to the options are: the lines must be set visible via "drawHGrid" property, "constantCellHeight" property set to 0, and the changes to the vertical extents can be recorded via "SetExtent" notification.

Default value: 0

allowChangeCellWidth BOOLEAN
If 1, the user is allowed to change horizontal extents of cells by dragging the horizontal grid lines. Prerequisites to the options are: the lines must be set visible via "drawVGrid" property, "constantCellWidth" property set to 0, and the changes to the horizontal extents can be recorded via "SetExtent" notification.

Default value: 0

Marks the marginal rows and columns as 'indent' cells. The indent cells are drawn with another color pair ( see indentCellColor, indentCellBackColor ), cannot be selected and scrolled. X1 and X2 correspond to amount of indent columns, and Y1 and Y2, - to the indent rows.

"leftCell" and "topCell" do not count the indent cells as the leftmost or topmost visible cell; in other words, X1 and Y1 are minimal values for "leftCell" and "topCell" properties.

Default value: 0,0,0,0

A three-state integer property, that governs the way clipping is applied when cells are drawn. Depending on kind of graphic in cells, the clipping may be necessary, or unnecessary.

If the value is 1, the clipping is applied for every column drawn, as the default drawing routines proceed column-wise. If the value is 2, the clipping as applied for every cell. This setting reduces the drawing speed significantly. If the value is 0, no clipping is applied.

This property is destined for custom-drawn grid widgets, when it is the developer's task to decide what kind of clipping suits better. Text grid widgets, "Prima::AbstractGrid" and "Prima::Grid", are safe with "clipCells" set to 1.

Default value: 1

Sets number of columns, including the indent columns. The number of columns must be larger than the number of indent columns.

Default value: 0.

A run-time property, selects width of a column. To acquire or set the width, "Measure" and "SetExtent" notifications can be invoked. Result of "Measure" may be cached internally using "cache_geometry_requests" method.

The width does not include widths of eventual vertical grid lines.

If "constantCellWidth" is defined, the property is used as its alias.

If defined, all rows have equal height, HEIGHT pixels. If "undef", rows have different heights.

Default value: undef

If defined, all rows have equal width, WIDTH pixels. If "undef", columns have different widths.

Default value: undef

If 1, horizontal grid lines between cells are drawn with "gridColor".

Default value: 1

If 1, vertical grid lines between cells are drawn with "gridColor".

Default value: 1

A run-time property. Selects horizontal offset in pixels of grid layout in pixel mode.
A run-time property. Selects vertical offset in pixels of grid layout in pixel mode.
Selects coordinates or the focused cell.
Selects the color of grid lines.

Default value: "cl::Black" .

The property selects the breadth of area around the grid lines, that reacts on grid-dragging mouse events. The minimal value, 0, marks only grid lines as the drag area, but makes the dragging operation inconvenient for the user. Larger values make the dragging more convenient, but increase the chance that the user will not be able to select too narrow cells with the mouse.

Default value: 3

Selects the background color of indent cells.

Default value: "cl::Gray" .

Selects the foreground color of indent cells.

Default value: "cl::Gray" .

Selects index of the leftmost visible normal cell.
If 1, the normal cells in an arbitrary rectangular area can be marked as selected ( see selection ). If 0, only one cell at a time can be selected.

Default value: 0

Sets number of rows, including the indent rows. The number of rows must be larger than the number of indent rows.

Default value: 0.

Selects index of the topmost visible normal cell.
A run-time property, selects height of a row. To acquire or set the height, "Measure" and "SetExtent" notifications can be invoked. Result of "Measure" may be cached internally using "cache_geometry_requests" method.

The height does not include widths of eventual horizontal grid lines.

If "constantCellHeight" is defined, the property is used as its alias.

If "multiSelect" is 1, governs the extents of a rectangular area, that contains selected cells. If no such area is present, selection is (-1,-1,-1,-1), and "has_selection" returns 0 .

If "multiSelect" is 0, in get-mode returns the focused cell, and discards the parameters in the set-mode.

If CACHE is 1, starts caching results of "Measure" notification, thus lighting the subsequent "columnWidth" and "rowHeight" calls; if CACHE is 0, flushes the cache.

If a significant geometry change was during the caching, the cache is not updated, so it is the caller's responsibility to flush the cache.

Nullifies the selection, if "multiSelect" is 1.
A bulk draw routine, called from "onPaint" to draw cells. AREA is an array of four integers with inclusive-inclusive coordinates of the widget inferior without borders and scrollbars ( result of get_active_area(2) call; see "get_active_area" in Prima::IntUtils ).

COLUMNS and ROWS are structures that reflect the columns and rows of the cells to be drawn. Each item in these corresponds to a column or row, and is an array with the following layout:

        0: column or row index
        1: type; 0 - normal cell, 1 - indent cell
        2: visible cell breadth
        3: visible cell start
        4: visible cell end
        5: real cell start
        6: real cell end

The coordinates are in inclusive-inclusive coordinate system, and do not include eventual grid space, nor gaps between indent and normal cells. By default, internal arrays "{colsDraw}" and "{rowsDraw}" are passed as COLUMNS and ROWS parameters.

In "Prima::AbstractGrid" and "Prima::Grid" classes <draw_cells> is overloaded to transfer the call to "std_draw_text_cells", the text-oriented optimized routine.

A bulk routine for drawing text cells, called from "std_draw_text_cells" .

SCREEN_RECTANGLES and CELL_RECTANGLES are arrays, where each item is a rectangle with exterior of a cell. SCREEN_RECTANGLES contains rectangles that cover the cell visible area; CELL_RECTANGLES contains rectangles that span the cell extents disregarding its eventual partial visibility. For example, a 100-pixel cell with only its left half visible, would contain corresponding arrays [150,150,200,250] in SCREEN_RECTANGLES, and [150,150,250,250] in CELL_RECTANGLES.

CELL_INDECES contains arrays of the cell coordinates; each array item is an array of integer pair where item 0 is column, and item 1 is row of the cell.

FONT_HEIGHT is a current font height value, cached since "draw_text_cells" is often used for text operations and may require vertical text justification.

Returns screen area in inclusive-inclusive pixel coordinates, that is used to display normal cells. The extensions are related to the current size of a widget, however, can be overridden by specifying WIDTH and HEIGHT.
Returns text string assigned to cell in COLUMN and ROW. Since the class does not assume the item storage organization, the text is queried via "Stringify" notification.
Returns a pair of integers, minimal and maximal breadth of INDEXth column or row in pixels. If AXIS is 1, the rows are queried; if 0, the columns.

The method calls "GetRange" notification.

Returns information about a cell in COLUMN and ROW, if it is currently visible. The returned parameters are indexed by "gsci::XXX" constants, and explained below: 

        gsci::COL_INDEX - visual column number where the cell displayed
        gsci::ROW_INDEX - visual row number where the cell displayed 
        gsci::V_FULL    - cell is fully visible
        gsci::V_LEFT    - inclusive-inclusive rectangle of the visible
        gsci::V_BOTTOM    part of the cell. These four indices are grouped
        gsci::V_RIGHT     under list constant, gsci::V_RECT.
        gsci::V_TOP    
        gsci::LEFT      - inclusive-inclusive rectangle of the cell, as if
        gsci::BOTTOM      it is fully visible. These four indices are grouped
        gsci::RIGHT       under list constant, gsci::RECT. If gsci::V_FULL
        gsci::TOP         is 1, these values are identical to these in gsci::V_RECT.

If the cell is not visible, returns empty array.

Returns a boolean value, indicating whether the grid contains a selection (1) or not (0).
Return information about point X, Y in widget coordinates. The method returns two integers, CX and CY, with cell coordinates, and eventual HINTS hash, with more information about pixe localtion. If OMIT_GRID is set to 1 and the pixel belongs to a grid, the pixels is treated a part of adjacent cell. The call syntax: 

        ( $CX, $CY, %HINTS) = $self->point2cell( $X, $Y);

If the pixel lies within cell boundaries by either coordinate, CX and/or CY are correspondingly set to cell column and/or row. When the pixel is outside cell space, CX and/or CY are set to -1.

HINTS may contain the following values:

"x" and "y"
If 0, the coordinate lies within boundaries of a cell.

If -1, the coordinate is on the left/top to the cell body.

If +1, the coordinate is on the right/bottom to the cell body, but within the widget.

If +2, the coordinate is on the right/bottom to the cell body, but outside the widget.

"x_type" and "y_type"
Present when "x" or "y" values are 0.

If 0, the cell is a normal cell.

If -1, the cell is left/top indent cell.

If +1, the cell is right/bottom indent cell.

"x_grid" and "y_grid"
If 1, the point is over a grid line. This case can only happen when OMIT_GRID is 0. If "allowChangeCellHeight" and/or "allowChangeCellWidth" are set, treats also "gridGravity"-broad pixels strips on both sides of the line as the grid area.

Also values of "x_left"/"x_right" or "y_bottom"/"y_top" might be set.

"x_left"/"x_right" and "y_bottom"/"y_top"
Present together with "x_grid" or "y_grid". Select indices of cells adjacent to the grid line.
"x_gap" and "y_gap"
If 1, the point is within a gap between the last normal cell and the first right/bottom indent cell.
"normal"
If 1, the point lies within the boundaries of a normal cell.
"indent"
If 1, the point lies within the boundaries of an indent cell.
"grid"
If 1, the point is over a grid line.
"exterior"
If 1, the point is in inoperable area or outside the widget boundaries.
Repaints cell with coordinates X and Y.
Recalculates internal geometry variables.
Marks all cells as selected, if "multiSelect" is 1.
An optimized bulk routine for text-oriented grid widgets. The optimization is achieved under assumption that each cell is drawn with two colors only, so the color switching can be reduced.

The routine itself paints the cells background, and calls "draw_text_cells" to draw text and/or otherwise draw the cell content.

For explanation of COLUMNS, ROWS, and AREA parameters see draw_cells .

Called when a cell with COLUMN and ROW coordinates is to be drawn on CANVAS. SCREEN_RECT is a cell rectangle in widget coordinates, where the item is to be drawn. CELL_RECT is same as SCREEN_RECT, but calculated as if the cell is fully visible.

SELECTED and FOCUSED are boolean flags, if the cell must be drawn correspondingly in selected and focused states.

Puts minimal and maximal breadth of INDEXth column ( AXIS = 0 ) or row ( AXIS = 1) in corresponding MIN and MAX scalar references.
Puts breadth in pixels of INDEXth column ( AXIS = 0 ) or row ( AXIS = 1) into BREADTH scalar reference.

This notification by default may be called from within "begin_paint_info/end_paint_info" brackets. To disable this feature set internal flag "{NoBulkPaintInfo}" to 1.

Called when a cell with COLUMN and ROW coordinates is focused.
Reports breadth in pixels of INDEXth column ( AXIS = 0 ) or row ( AXIS = 1), as a response to "columnWidth" and "rowHeight" calls.
Puts text string, assigned to cell with COLUMN and ROW coordinates, into TEXT_REF scalar reference.

Exactly the same as its ascendant, "Prima::AbstractGridViewer", except that it does not propagate "DrawItem" message, assuming that the items must be drawn as text.

The class implements cells data and geometry storage mechanism, but leaves the cell data format to the programmer. The cells are accessible via "cells" property and several other helper routines.

The cell data are stored in an array, where each item corresponds to a row, and contains array of scalars, where each corresponds to a column. All data managing routines, that accept two-dimensional arrays, assume that the columns arrays are of the same widths.

For example, "[[1,2,3]]]" is a valid one-row, three-column structure, and "[[1,2],[2,3],[3,4]]" is a valid three-row, two-column structure. The structure "[[1],[2,3],[3,4]]" is invalid, since its first row has one column, while the others have two.

"Prima::GridViewer" is derived from "Prima::AbstractGridViewer".

Default value: 1
Default value: 1
Run-time property. Selects the data in cell with COLUMN and ROW coordinates.
The property accepts or returns all cells as a two-dimensional rectangular array or scalars.
A read-only property; returns number of columns.
A read-only property; returns number of rows.

Inserts one-dimensional array of scalars to the end of columns.
Inserts two-dimensional array of scalars to the end of columns.
Inserts one-dimensional array of scalars to the end of rows.
Inserts two-dimensional array of scalars to the end of rows.
Removes LENGTH columns starting from OFFSET. Negative values are accepted.
Removes LENGTH rows starting from OFFSET. Negative values are accepted.
Inserts one-dimensional array of scalars as column OFFSET. Negative values are accepted.
Inserts two-dimensional array of scalars in column OFFSET. Negative values are accepted.
Inserts one-dimensional array of scalars as row OFFSET. Negative values are accepted.
Inserts two-dimensional array of scalars in row OFFSET. Negative values are accepted.

Descendant of "Prima::GridViewer", declares format of cells as a single text string. Incorporating all functionality of its ascendants, provides a standard text grid widget.

Returns text string assigned to cell in COLUMN and ROW. Since the item storage organization is implemented, does so without calling "Stringify" notification.

Dmitry Karasik, <dmitry@karasik.eu.org>.

Prima, Prima::Widget, examples/grid.pl