Spreadsheet v 0.3

This is to provide spreadsheet-style code editing, for highly tedious editing, like
renumbering numerous equates, creating large Select Case structures, and so on.
It will also be used in list operations for  "flex-editing" which is the reason for the
extra features for selection, column grouping and special editing modes. It will
hopefully support fancy formatting too, eventually.
 It seems this could become fairly useful as a general purpose spreadsheet too. As
a spreadsheet it is intended more as a utility, but it might eventually be full-featured.

Last updated: October 17, 2005

Some current features:

• 65536 rows and up to 700 columns (it's set at the standard 256 for now)
• Compiles to about 90KB
• Most, if not all standard spreadsheet keyboard navigation
• Selection expansion to contiguous used cells by Ctrl + *
• Selection expansion by Ctrl+Shift+ Arrow keys
• Selection of rows or columns by clicking
• Selections are additive and toggle when pressing Ctrl
• Open file by toolbar or drag-and-drop (tab-delimited format only)
• Cut, copy and paste
• Rows and columns resizeable with the mouse, Alt+Arrow keys or Alt+Shift+Arrow keys
• Math evaluation (no cell references supported yet)
• Auto recalculation of sheet
• Formulas are checked when they're entered
• Drag-fill is partly done (just the mouse-ability)
• Scrolling, including mouse wheel
• Panning with middle button (jerky)

Some current (temporary) limitations:
No file save
No insert/delete rows and columns
Single sheet
No undo/redo
No sorting
No fancy formatting

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Some of the Planned Design Details and Features:

Auto, or manual sorting

Selections may be partly or completely discontinuous. The current selection
at any stage should also be preservable to prevent accidental loss of complex
selections. An additional safeguard will be the undo and redo for selection
changes.

Switch to edit mode with Ctrl+Enter or Shift+Enter

To quickly change the direction of cell cursor movement when Enter is
pressed: press ??? then an arrow key (undecided).

Data in several columns can be "grouped", so that they can be operated on
all together. The  grouped columns need not be adjacent. This is to simplify
operations such as selecting, dragging and sorting.

Selection Behaviour

• It will be similar to that of the listview control, and have some
  enhancements.
• No selection is made at the current cursor position until the user
  makes it (in contrast of the listview)
• Pressing SHIFT sets the selection anchor
• Holding SHIFT and pressing the arrow or page keys adjusts the
  selection
• from the current anchor position to the new cursor position
• Holding the Ctrl key without the SHIFT key allows the anchor to be moved
  by the arrow and page keys while preserving the current selection 
• In contrast to the listview control, dragging selects multiple items
• Selections can be made in either additive or toggle mode. In toggle mode,
  overlapping portions of two or more selections will be deselected. Toggle
  mode is activated by ???
• Existing selections can be preserved while making additional ones by...???
• Pressing ESC clears all selections
• Undo a selection action by pressing Ctrl+Shift+Z...???
• Redo a selection action by pressing Ctrl+Shift+Y...???
  

Editing Operations
These operations are done by clicking, shortcuts or using the menu on a selection.

• Delete contents
• Delete row
• Merge cell contents with a space
• Merge cell contents without a space
• Split cell contents
• Sort ascending or descending
• Join selected items
• Send selected items to the end of the list
• Send selected items to the top of the list
• Group cells by column

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Spreadsheet Internals
 This covers a few of the more difficult aspects of the spreadsheet code (the design
has been changed from that originally described here).

Keeping Track of Used Cells
A one-dimensional string array is used for the cells' contents, and a UDT
array to hold each one's row and column positions.
Type CELLCOORD Dword
    col As Word
    row As Word
End Type

Selection State Storage
This is stored in the form of descriptions of selection actions. This allows
it to function as an undo/redo buffer for selections, in addition to being a
compact form of storage. A multiple selection uses two elements of the
array.
Type SELECTIONEVENT Byte
    typ     As Byte
    col     As Word
    row     As Word
End Type

The type can be any compatible combination of the following:

• Additive
• Toggle
• None
• Single
• Block
• Done

Format State Storage
This will be done the same way as for the selection states.

Applying Selection State and Format
Information to the Current Display
A two-dimensional byte array is used to hold the selection states and
formatting of all cells which are currently visible. It is refilled each time the
grid is displayed from the data in the selection-event and format-event
arrays.
 As the grid is drawn, the cell-coordinate (CELLCOORD) array is searched
for each visible cell's column and row positions, determine whether it's used
or not, and its contents are displayed if so.

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The source code is in the "grid" folder of the CVS directory.
Browse CVS


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This project is sponsored by TheirCorp
(formerly TheirWare Corporation)