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Hi ! Firest, sorry for my bad english.
I try to create a simple 2D graph scene for learning purpose. A very great article from Bob Powel
(http://www.bobpowell.net/graphicsstack.aspx) who gave me a bese to start.
So, I understand that to draw an "objects chain" (like bones chain), I must start with an identity matrix and rotate/translate it with the local transform of the bone to draw. At the end of a chain, I reset my "drawing matrix" and I can draw others bones chains.
So, the Bone class only store a local matrix and the drawing method of my Renderer control only use this local transform to draw an object relatively from its parent.
All is good. I can modify and read the local translation or rotation for each bone easilly.
Now, my problem is, I want to be able to read/modify the absolute position or rotation of a nested object. The reason is simple.
Imagine I have a root bone with one child. The root bone have an absolute position (10, 10) and an absolute rotation of 45°. The child bone has a local translation of (30, 0) and a rotation of 45°. We can easilly say that this child bone has an absolute rotation of 90°. I can easilly compute the absolute transform from the local one.
So now I can get/set local transform and get absolute transform, but I can't find a way to set the absolute transform.
I understand I must translate an absolute matrix to a local matrix, but what could be the pseudo code or steps to achieve this ?
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Are you aware of the Graphics.Transform property? and the Graphics.ResetTransform() method?
I'm not sure what your code organization is, I don't think I would need any of those when painting a hierarchical object: the root of the drawing should just get the original Graphic from the PaintEventArgs parameter, then adapt and pass on to its children, each of them undoing their transformation change when they are done.
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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Yes, I know Graphics.Transform / ResetTransform and Save / Restore
This is a pseudo code for my main drawing function ...
Private Sub MainDrawing
For each bone in bones list (bone class inherits TreeNode.)
-Save the Graphics tranform (Graphics.Save)
-Call a recursive function (DrawBonesRecursively)
->DrawBonesRecursively(e.Graphics, bone)
-Restore the original Graphics tranform (Graphics.Restore)
End For
End Sub
Private Sub DrawBonesRecursively(g as Graphics,bone as Bone)
-Get the LOCAL matrix of the bone
-Rotate and Translate Graphics transform with LOCAL matrix values
-Get the untransformed GraphicsPath of my bone
-Draw it
For each childBone in bone.Nodes
-Call this sub itself for recursion. For "bone" argument, I pass "bone.
End For
End Sub
My drawing function only need the local coordinates of each bone. So, I can get/set easilly the LOCAL transform, and I'm only able to compute the absolute transform and read it, but if I want to set it with absolute values, I must convert it with local values to make my function drawing.
Do you understand my problem ? Sorry I'm not very comfortable with the kind of explanations in english
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The transformations you get from ScaleTransform and the like are cumulative, so child bones get their parent's matrix automatically; you do need to add an undo, so just before End Sub insert
Undo Rotate and Translate Graphics transform with LOCAL matrix values
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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Question:
My company has recently bought some fancy usercontrols on the net.
These controls can do a lot, but some of them require databinding.
This is something I am not familiar with and neither is my company.
I am quite convinced of the advantages of databinding, but not when it's done in the designer. The designer generates a lot of code, both in VB and SQL and puts lots of items in your toolbox and componentstray. Bottomline is that I have no idea what I'm doing in the designer. But this is also because I'm not familiar with creating datasets in the designer.
So what do you say? Should I just keep on trying and make my dataset, tables and binds in the designer or is programming the whole thing easier/more scalable/better maintainable etc.? What are the pro's and cons, code vs. designer.
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IMHO, using the designer limits your options and creates a ton of "mystery" code that goes in places you're not aware of.
I never use the designers for datasets. I prefer to write my own code for simplicity and maintainability.
BTW: Databind is done all the time without using the deisgners. When you set a DataSource property to some collection or DataTable or DataSet, you're doing databinding. I can't believe nobody in your company knows about this.
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We never use the datasource property.
We always fill every cell in a datagrid or every textbox on a form programatically.
There's a bit more to it than that, and there's some benefits to it.
But let's just say we really never use databinding 
Databinding has always been a kind of taboo. Until now.
And the more I do with it (design-time), the more it becomes taboo for me again 
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If/when I use datagrids I make them readonly, and bind(set the datasource) to a
list/array/collection of something. And edit/modify the data through dedicated popup windows/user controls.
All the best,
Dan
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Naerling wrote: We always fill every cell in a datagrid or every textbox on a form programatically
Wow. Talk about a ton of code that's slow to fill a grid and could all be replaced with a single assignment statement.
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Sorry for the long answer but here goes.
If you ask me don't use design time databing, hell even better(or worse depends on taste) don't
use datasets/datatables.
I had some experinces with datagrids and automated vodoo magic that were very unpleasant. I
just didn't have a clue at was the error was.
Since then I always create classes or structs/enumns depends on the job ata hand.
Anywho I always create classes that map the tables and/or business model and use
Datareaders to get the datas in those customized object models. It takes a little longer to code
but the benefits of debugging itself not to mention maintanability/scalability...
are totally worth it.
- You are in control.
- You tell it(the app/progra) what to do. Not some vodoo magic and pray to god it all goes well.
Maybe I'm beeing a little extreme but I wouldn't use for anything in the world in a real world app.
Sure some quick and dirty tests and the likes, yeah go ahead saves time. But real world apps NO.
Just my thoughts.
All the best,
Dan
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I was kind of thinking the same thing. But I do want to give datatables/sets a try.
We are now working with lots of classes and properties.
But it's a lot of work, especially if you have some master detail stuff.
Actually we're all kind of tired of having to type:
Textbox1.Text = datarow("field1")
Textbox2.Text = datarow("field2")
Textbox3.Text = datarow("field3")
...
Textbox50.Text = datarow("field50")
You get the idea
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Naerling wrote: You get the idea
yeah, you really should choose more descriptive TextBox and field names.
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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Something like txt1, txt2 right? 
Just think about the cost/type reduction. 
All the best,
Dan
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Har har... Har
Using connection As New SqlClient.SqlConnection(My.Settings.MyConnectionString)
Using cmd As New SqlClient.SqlCommand("select * from smartasses where name = @name", connection)
cmd.Parameters.Add("name", SqlDbType.VarChar, 50).Value = GetUserFromPostAbove()
connection.Open()
Try
Using reader As SqlClient.SqlDataReader = cmd.ExecuteReader
While reader.Read
Dim gridRow As New DataGridViewRow
gridRow.CreateCells(gridSmartAsses)
gridRow.Cells(gridSmartAsses.Columns("name").Index).Value = reader.Item("name")
gridRow.Cells(gridSmartAsses.Columns("age").Index).Value = reader.Item("age")
gridRow.Cells(gridSmartAsses.Columns("message").Index).Value = reader.Item("message")
gridRow.Cells(gridSmartAsses.Columns("funny").Index).Value = reader.Item("funny")
' ... Up to about 20 columns.
gridSmartAsses.Rows.Add(gridRow)
End While
End Using
Finally
connection.Close()
End Try
End Using
End Using
That's just no way to fill numerous grids with 15 to 20 columns 
And I know this query looks like it will return only 1 smartass, being GetUserFromPostAbove() (and yes, that name IS in the table :p ), but you can see why we don't want to fill our grids like this anymore
I never use the SqlClient namespace by the way, we have our own simplified company tool which is top secret! 
So feel free to comment on the code as you see fit. I am here to learn as well
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Urghhh VB.
Please take your capitalisation out of our pristine, brace friendly forum.
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All those
gridRow.Cells(gridSmartAsses.Columns("name").Index).Value = reader.Item("name")
lines are identical except for a string, so you could "for each" them with the string pulled from a collection. In the end I would stuff the entire try block into a separate method, that is generic and needs to be written just once.
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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So you'd pass the datagridview and two list(of string) (column names and field names are not always equally named) to a function called FillGrid or something?
Sounds like it would work, but then you'd have to iterate through gridcolumns and datatable columns
And if you have some exception like gridRow.blabla.value = reader.Item(0) & reader.Item(1) it wouldn't work, or if you want to colour every row where (some condition) or... And we do that sometimes
Actually those were the advantages of filling each row seperately.
But I guess that's not possible with databinding either... 
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If that was meant as a question, then yes you pass parameters for everything you want to be able to change from the outside. As always. And you can forgo exception handling inside the method, and leave that to the caller, as he is more aware of what should be reported if and when something goes wrong.
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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The real answer to your question is "That is the question".
Hope it helps. 
All the best,
Dan
modified on Wednesday, January 26, 2011 3:14 PM
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No, that is the question...
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Naerling wrote: Actually we're all kind of tired of having to type:
..how about generating it?
I are Troll
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Naerling wrote: These controls can do a lot, but some of them require databinding.
To what, actually? I'm binding a lot from generic lists and array's, as a quick and easy way to display data.
Naerling wrote: This is something I am not familiar with and neither is my company.
There's always MSDN[^] 
I are Troll 
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Sure there's MSDN, but they won't tell me to not use their designer features 
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Are you using the "Settings"-tab in the project page? That's a code-generator too
The page on MSDN describes databinding in a more broad sense then binding an ADO table to a grid. Your 3rd party controls might want to bind to CLR-properties. What does the documentation of the 3rd party controls say?
I are Troll
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