1. Pixel Editor PX 1.0
Ajay Prasad

2. Agenda
Utility
Terminology
Design
Interface
Future
Reference
PX 1.0

3. Terminology
“The Component Object Model (COM) is a software architecture that allows applications to be built from binary software components. COM is the underlying architecture that forms the foundation for higher-level software services, like those provided by OLE (Object Linking and Embedding). OLE services span various aspects of commonly needed system functionality, including compound documents, custom controls, interapplication scripting, data transfer, and other software interactions. “
Client Process
On the same machine
Server Process
Component
COM
Client
PX 1.0

4. ArcObjects
Terminology
ArcObjects™ is the development platform for the ArcGIS™ family of applications such as ArcMap™, ArcCatalog™, and ArcScene™
ArcObjects is a framework that lets you create domain-specific components from other components.
ArcObjects provides an infrastructure for application customization that lets you concentrate on serving the specific needs of your clients.
ArcObjects is built using Microsoft’s Component Object Model (COM) technology.
PX 1.0

5. Key ArcObjects Used….. ICommand ITool IMap IEnvelope IPoint
Terminology
ESRI Object Library as project reference
ICommand
Provides access to members that define a COM command.
To query the properties of a COM command or to create your own COM command.
ITool
Provides access to members that define a tool.
To query the properties of a built-in tool or to create your own COM tool.
IMap
Provides access to members that control the map.
To display data from various data sources.
IEnvelope
Provides access to methods and properties of envelopes.
Envelope is defined by the XMin, XMax, YMin, and YMax of the object.
IPoint
Provides access to members that define two dimensional points.  
Point represents a specific (X, Y) location in a the two-dimensional XY-Plane.  A Point may also have Z, M, and ID attributes associated with it. 
PX 1.0

6. Key Sub Routines and Functions…
Design
Function setDocMap(mApp As IApplication) As IRaster
Sets document’s focus map and finds Raster layers present
Sub Map2Dataset(ByVal pMapPoint As IPoint)
Converts pMapPoint.X and pMapPoint.Y to Column number and Row number
Public Sub showPixelMap(pRaster As IRaster, pPoint As IPoint)
Reads the Pixel values from the Raster layer and displays in 3 X 3 Table.
Private Sub cmdSave_Click()
Write the new pixel values to the Raster Layer.
Private Sub updateSymbology()
Updates the Symbology to stretched category with new pixel values (Optional)
PX 1.0

7. The Tool Interface Raster Layers in the map Shows “Edit history”
Zoom out to the Extent
Get the Pixel values around specified
Row and Column
Zoom to the Column and Row
Pixel Values
Overwrite values with new one
Reset with old values
Change Symbology to Stretched Category
PX 1.0

8. Significance
Utility
Attribute Table
Unable to edit value of the pixel at a particular coordinate.
PX 1.0 enables edit feature at desirable coordinates.
PX 1.0

9. Rows and Columns of the Pixel Display Table can be modified
Version “ PX 1.1 ”
Future
Rows and Columns of the Pixel Display Table can be modified
Test with different data types and grids
To be compatible with MapWindow 3.0
More utilities which helps users to do the edits more efficiently
Suggestions and Feedback from users
PX 1.0

10. Acknowledgment and Reference
Dr David G Tarboton
Professor, Civil and Environmental Engineering
Utah State University
Exploring ArcObjects Vol. I and II
Geographic Data Management – Edited by Michael Zeiler
GIS by ESRI TM
PX 1.0

11. PX 1.0

12. PX 1.0

13. Object Linking and Embedding
Terminology
An object system created by Microsoft. OLE lets the author invoke different editor components to create a compound document.
Microsoft's comprehensive object strategy is built around the OLE object model and is designed to provide developers with a consistent and open standard for defining what an object is and how objects interact with one another.
OLE technology is now an integral part of custom controls, creating a new open standard for component-based software development.
PX 1.0

14. ICommand and ITool
Terminology
ICommand interface sets command properties such as caption, name, category, bitmap, status bar message, tool tip, help context id and help file, enabled state, and checked state. It also defines what action happens when the command is clicked.
When you are creating a new COM tool, you need to implement both the ICommand interface and the ITool interface in your class code. With the ITool interface you can define what occurs on events such as mouse move, mouse button press/release, keyboard key press/release, double-click, and right click.
PX 1.0

15. IEnvelope
Terminology
PX 1.0

16. IPoint
Terminology
PX 1.0

17. IMap
Terminology
The IMap interface is a starting point for many of the tasks one does with a Map.
Use IMap to add, delete, and access map layers containing data from various sources including feature layers and graphics layers; associate map surround objects (legends, scale bars, etc) with the Map; access the various properties of a Map including the area of interest, the current map units, and the spatial reference; select features and access the Map's current selection.
PX 1.0

18. setDocMap
Design
Function setDocMap(mApp As IApplication) As IRaster
'no input raster
Set pMxDoc = mApp.Document
Set pActiveView = pMxDoc.FocusMap
Set pMap = pMxDoc.FocusMap
Set pEnumLayer = pMap.Layers
Set pLayer = pEnumLayer.Next
If isloaded = False Then
If TypeOf pLayer Is IRasterLayer Then
Set pRLayer = pLayer
pathName = pRLayer.FilePath
Set setDocMap = pRLayer.Raster
End If
Else
Dim i As Integer
cboItem = IIf(frmPixelMap.cboRasterLayers.ItemData(frmPixelMap.cboRasterLayers.ListIndex) < 0, 1, frmPixelMap.cboRasterLayers.ItemData(frmPixelMap.cboRasterLayers.ListIndex))
pEnumLayer.Reset
For i = 0 To cboItem
If TypeOf pLayer Is IRasterLayer Then Set pLayer = pEnumLayer.Next
Next
popCombo
End Function
End Sub
PX 1.0

19. Map2Dataset Design Sub Map2Dataset(ByVal pMapPoint As IPoint)
On Error GoTo myErr
Dim pRasProp As IRasterProps
Dim nx As Double, ny As Double
Dim a1 As Double, b1 As Double, a2 As Double, b2 As Double
If pMapPoint Is Nothing Then
MsgBox "Map point object is null", vbCritical, "Raised Error"
Exit Sub
End If
Set pRasProp = pRas
g_Wid = pRasProp.Width
g_Hgt = pRasProp.Height
Dim pEnv As IEnvelope
Set pEnv = pRasProp.Extent
pEnv.QueryCoords g_ex1, g_ey1, g_ex2, g_ey2
nx = g_Wid
ny = g_Hgt
a1 = (nx) / (g_ex2 - g_ex1) ' # of pixels / map unit -- for x-axis
b1 = -g_ex1 * a1
a2 = (ny) / (g_ey2 - g_ey1) ' # of pixels / map unit -- for y-axis
b2 = -g_ey1 * a2
PX 1.0

20. ……………………. Design '/////For zoom in purpose ac1 = a1 ac2 = a2 bc1 = b1
Dim pDataPoint As IPoint
Set pDataPoint = New Point
Dim v As Long
pDataPoint.X = Int(pMapPoint.X * a1 + b1) 'the number of rows to the point
v = Int(pMapPoint.Y * a2 + b2)
pDataPoint.Y = g_Hgt - v - 1 'number of columns to the point
Set pMapPoint = pDataPoint
frmPixelMap.Show
frmPixelMap.ZOrder (0)
frmPixelMap.showPixelMap pRas, pMapPoint
isloaded = True
Set pDataPoint = Nothing
myErr:
If Err.Number <> 0 Then MsgBox "Map2Dataset:" & Err.Description
End Sub
PX 1.0

21. showPixelMap
Design
Public Sub showPixelMap(pRaster As IRaster, pPoint As IPoint)
' Dim pRaster As IRaster
Dim vArr As Variant
On Error GoTo er
Screen.MousePointer = vbHourglass
' get current band index
Dim pRD As IRasterDataset
Dim pBC As IRasterBandCollection
Set pRD = OpenRasterDataset(pathName)
Set pBC = pRD
Set g_pEditBand = pBC.Item(0)
Set g_pTrans = g_pEditBand
g_Edits = 0
g_pTrans.UndoLevels = 5
Set pRasterProp = pRaster
' create pixelblock the size of the input raster
Set pSize = New DblPnt
pSize.SetCoords 3, 3
Set pPixelBlock = pRaster.CreatePixelBlock(pSize)
Set pRawPixel = g_pEditBand
' get vb supported pixel type
' pRasterProp.PixelType = GetVBSupportedPixelType(pRasterProp.PixelType)
' get pixeldata
xCell = pPoint.X
yCell = pPoint.Y
'showing Rows and columns
txtColumn = xCell
txtRow = yCell
Set pOrigin = New DblPnt
pOrigin.SetCoords pPoint.X - 1, pPoint.Y - 1
pRawPixel.Read pOrigin, pPixelBlock
vArr = pPixelBlock.SafeArray(0)
PX 1.0

22. ………………….. Design ' show pixel data in the grid Dim inc As Integer
For irow = 0 To 2
' set cell size
For icol = 0 To 2
txtEdit.Item(inc) = IIf(vArr(icol, irow) >= 0, FormatNumber(vArr(icol, irow), 6), "Nodata")
resetValues(inc) = txtEdit.Item(inc)
inc = inc + 1
Next icol
Next irow
' cleanup
Set pRaster = Nothing
Set pRasterProp = Nothing
Set pSize = Nothing
Set pOrigin = Nothing
Screen.MousePointer = vbDefault
Exit Sub
er:
If Err.Number <> 0 Then
MsgBox "Failed to get pixel data: " & Err.Description
For inc = 0 To 8
txtEdit.Item(inc) = ""
Next
End If
End Sub
PX 1.0

23. cmdSave_Click() Design Private Sub cmdSave_Click()
On Error GoTo catchError
Dim pSafeArray As Variant, irow As Integer, icol As Integer
Dim pBandCol As IRasterBandCollection
Dim pBand As IRasterBand
Dim X As Integer, Y As Integer, i As Integer
For i = 0 To 8
If IsNumeric(txtEdit(i)) = False Then
MsgBox "Invalid number.", vbExclamation + vbOKOnly
Exit Sub
End If
Next i
pSafeArray = pPixelBlock.SafeArray(0)
' set cell size
X = xCell
Y = yCell
Dim inc As Integer
inc = 0
For irow = 0 To 2
For icol = 0 To 2
pSafeArray(icol, irow) = FormatNumber(txtEdit.Item(inc), 6)
inc = inc + 1
Next icol
Next irow
PX 1.0

24. ………………… Design 'create a dblpnt Dim pPnt As IPnt Set pPnt = New DblPnt
g_pTrans.Start
pPnt.SetCoords xCell - 1, yCell - 1
pRawPixel.Write pPnt, pPixelBlock
'/////////////////////////////////////////////////////////
If chkUpdateSymbology.Value = 1 Then updateSymbology
'///////////////////////////////////////////////////////
pActiveView.PartialRefresh esriViewGeography + esriViewGraphics, Nothing, Nothing
If chkUpdateSymbology.Value = 1 Then pMxDoc.UpdateContents
g_Edits = g_Edits + 1
g_pTrans.End
Exit Sub
catchError:
helloError Err.Number, Err.Description
End Sub
PX 1.0

25. updateSymbology() Design Private Sub updateSymbology()
Dim pRenLayer As IRasterLayer
Set pRenLayer = pMap.Layer(IIf(cboRasterLayers.ListIndex > -1, cboRasterLayers.ItemData(cboRasterLayers.ListIndex), 0))
Dim pRaster As IRaster
Set pRaster = pRenLayer.Raster
' Create renderer and QI RasterRenderer
Dim pStretchRen As IRasterStretchColorRampRenderer
Set pStretchRen = New RasterStretchColorRampRenderer
Dim pRasRen As IRasterRenderer
Set pRasRen = pStretchRen
' Set raster for the renderer and update
Set pRasRen.Raster = pRaster
pRasRen.Update
' Define two colors
Dim pFromColor As IColor
Dim pToColor As IColor
Set pFromColor = New RgbColor
pFromColor.RGB = RGB(255, 0, 0)
Set pToColor = New RgbColor
pToColor.RGB = RGB(0, 255, 0)
Create color ramp
Dim pRamp As IAlgorithmicColorRamp
Set pRamp = New AlgorithmicColorRamp
pRamp.Size = 255
pRamp.FromColor = pFromColor
pRamp.ToColor = pToColor
pRamp.CreateRamp True
PX 1.0

26. ………………………..
Design
' Plug this colorramp into renderer and select a band
pStretchRen.BandIndex = 0
pStretchRen.ColorRamp = pRamp
' Update the renderer with new settings and plug into layer
pRasRen.Update
Set pRenLayer.Renderer = pStretchRen
End Sub '
PX 1.0