How do I?

[killer_cobra]

Hi all,

I am wondering how I can make a virtual invisible grid on an image control.

Example:

I have an image control that is 6000 x 4000, and I want the grid to be say 640x480 but span the whole image control. So if I were to click on the very top left corner of the image in the control, I could get the grid co-ordonates and they would be something like : 632x478.

I hope this is enough to go on, it's a hard question to explain, but that is my attemp. I imagine there would be some sort of API or math function that would let me do this, but I know not of them.

Thanx a million in advance,

Scott

[eiSecure]

um....that's kinda confusing.


What do you mean by

I have an image control that is 6000 x 4000...

[killer_cobra]

I mean the property values for width and height of the image control.

I set them for 6000 x 4000.

[eiSecure]

Well...you have to convert those to twips, and then set the form to full-screen or something.

Then, you have to determind the coordinates of the mouse (mouse x, mouse y, in the mouse_move event, I think.) and add 6000 or 4000 to it.

[rjlohan]

Don't do that!

Convert your scale mode for both the form and picture box to 3-Pixels. Twips are bloody gay. There is no visible change except for every 15 twips, which = 1 pixel. Why have a gay scale that doesn't do anything?

Anyway. Do that ^ and then add the following code to your MouseDown/DragDrop event or whatever (not Mouse_Click - it doesn't pass the X/Y parameters):

X = X - (X Mod 32)
Y = Y - (Y Mod 32)

This will snap the mouse position (X,Y) to the top-left corner of the grid square you click in. (I think this is what you want... am I right?)
Note : This is for a grid of 32x32 pixel squares. Change the 32 as you wish.

[eiSecure]

Notice that twips adjusts automatically to a computer's screen resolution. 15 pixels will look different on different computers, but i don't think twips do.

[rjlohan]

WEll that's on a 15"/17" monitor, with 800x600 screen settings.
That's pretty standard. And anyway, Twips still suck arse.

[eiSecure]

Sorry, but many people are on 1024x720. If you specify everything in pixels, you may have compatability problems.

[chrisjk]

That is easily solved by the Screen.TwipsPerPixelX and Screen.TwipsPerPixelY properties.

It is not always 15, those properties will give the exact values depending on the res in question

[killer_cobra]

Many thanks to all who input on my thread, but I have found a simple way of doing what I needed to do.

Private Sub Form_Load()

Dim ResWidth, ResHeight

ResWidth = Screen.Width \ Screen.TwipsPerPixelX
ResHeight = Screen.Height \ Screen.TwipsPerPixelY

End Sub

Private Sub Image1_MouseMove (Button As Integer, Shift _
As Integer, X As Integer, Y As Integer)

Dim strDataX, strDataY, outDataX, outDataY

strDataX = X \ ResWidth
strDataY = Y \ ResHeight

outDataX = X \ strDataX
outDataY = Y \ strDataY

PosX.Text = outDataX
PosY.Text = outDataY

End Sub

Now from this, it doesn't matter what the initial resolution is, as it will automatically be taken into account during the form_load sub.

Thanx a million anyways for trying to help, it's much appreciated!!!!

Scott