8/6/2019 Vb.net Clock

1/13

The Challenge

The challenge is to create a project from scratch, which focuses just as much on how to rotate an

image as it does on doing it all in code. From 'scratch', 'home-made', applications are whatis being looked for. Have you got what it takes?

Concept

The concept to rotating images is simple. First, you find a place to put the corners of the picture,then you map the pixels and a rotated image is made.

But wait, that sounds like a lot of work.

Well, it is. Not just for you the programmer, but also for the program. To do this would take atremendous amount of resources, and time (at the computers scale).

There has GOT to be a better way.

Luckily, there is. For this subject, the Graphics class is held in high esteem. Not just because itcan do what we want and more, but also because one can be found residing in the

PaintEventArgs of a form, critical to displaying images, diagrams, and other things at runtime.

This 'WonderClass' is great and will seem to be the center of attention for our code.

8/6/2019 Vb.net Clock

2/13

But before we can get to the code...We need a respectable GUI!

GUI

Create a new VB project (note this app is possible in the express editions of Visual Studio):

Name it PocketWatchVB and click OK.

When a blank form appears, change:

FormBorderStyle to FixedSingle

We do this so that the user can't resize the form, causing possible errors in the future.

In order to give a smooth animation, set DoubleBuffered to True. This will make sure that youdon't get any animation flashes, or bad quality.

8/6/2019 Vb.net Clock

3/13

Once again, be sure that the style is set to FixedSingle.

Images

8/6/2019 Vb.net Clock

4/13

Before you do the next step, I would recommend that you have the files that are going to be usedas the Background and watch hands. You can either download them below, make your own, or

you can use the source code to retrieve the images (SRC.zip\Watch\Resources).

If you are going to make your own images, the picture size that this article is made for is

256x256. They should all have a transparent background, and the hands should be createdslightly smaller than the watch (but the image size must still be 256x256).

y Hour handy Minute Handy Second Handy The Watch Background

Resourceful Import

Import the four Images you should have saved, by changing Form1's BackgroundImage and

importing all four images.

Import all four images into the .resx file.

8/6/2019 Vb.net Clock

5/13

Choose (none).

None? The whole purpose of choosing none after we imported the pictures in Resources is sothat we don't have to worry about outside paths in our code, the program is more portable, and it

makes the code cleaner to reference to resources. So don't set any BackgroundImages this was

just for the sake of importing resources.

8/6/2019 Vb.net Clock

6/13

Make the size of the form 370,370.

This would put our images in the dead-center of the form. Just for looks. :)

8/6/2019 Vb.net Clock

7/13

Checkpoint 1

If your form looks like this, Good Job! ;)

The key point is the fact that this is a blank form. To help out the 'Homemade' aspect everything

is done at runtime (actually it's much faster this way, and is better for overlaying pictures).

8/6/2019 Vb.net Clock

8/13

Yes, I photo-imposed an icon. Like it?

Coding It All

In order to get the idea of what needs to be done before we start coding, let's use a table.

Step 1 Timer tick

Step 2 Repaint form

Step 3 Paint Background

Step 4 Find Hour

Step 5 Format Hour into 12-hour

Step 6 Find minute

Step 7 Find all rotation angles

Step 8Rotate the secondhand -

overlay it

Step 9

Rotate the minutehand -

overlay it

Step 10Rotate the hour hand - overlay

it

It is easy to see that most of the code will be used to rotate and overlay the hands of the clock,

while the first half of the procedures are spent on getting to that point.

8/6/2019 Vb.net Clock

9/13

Declare!

Before everything will work the way it should, some declarations are needed. These are the ones

necessary to the success of this project.

Import these in the Declarations Area:

CollapseImports System.Windows.Forms

Imports System.Drawing

Imports System.Drawing.Drawing2D

Then declare the following as variables of their specific type. We will use these later:

Collapse

Dim clockHour As DoubleDim clockmin As Integer

Dim hourAng As Integer

Dim minAng As Integer

Dim secAng As Integer

Dim secBMP As Image = (My.Resources.secondHand)

Dim minBMP As Image = (My.Resources.minuteHand)

Dim hourBMP As Image = (My.Resources.hourHand1)

Dim watchBMP As Image = (My.Resources.PocketWatchProj)

Declaring our BMPs before the code runs helps so that we can have everything run smoothly. Onthe other hand, we need to dispose of them before we close our form. To do this, add a

Form1_FormClosed() event handler.

CollapsePrivate Sub Form1_FormClosed(ByVal sender As Object, _ByVal e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed

secBMP.Dispose()

minBMP.Dispose()

hourBMP.Dispose()

watchBMP.Dispose()

End Sub

8/6/2019 Vb.net Clock

10/13

Painting

OK, down to business. The main muscle of our code will live within the Form1_Paint() event

handler. This is where we will literally 'paint' the form. Our painters will be Graphics classes

that inherit PaintEventArgs in a way that lets us 'paint' the form. You can also paint controls,

panels, and many other things, but the code might need to be tweaked.

Collapsee.Graphics.DrawImage(WatchBMP, 0, 0)

To begin, let us paint our pocketwatch onto the back of our form.

Since this is within the Form1_paint() Event handler, e refers to the PaintEventArgs. This

class allows us access into the Graphics painters that will paint the form. Here we are justtelling the 'painters' to paint our picture(which is in Resources) at the point (0,0).

Collapse

'make 12-hour instead of 24-hour

clockHour = Now.TimeOfDay.Hours

If clockHour > 12 Then

clockHour -= 12

ElseIf clockHour = 0 Then

clockHour = 12

End If

'Set the angles for minute and hour

hourAng = 30 * ClockHourminAng = 6 * Now.TimeOfDay.MinutessecAng = 6 * Now.Second

Before we get our 'painters' to paint the clock's hands, we need to tell them where and how to

paint. So this code converts the normal 24-hour time format into the common analog format of

12-hour. It then calculates the angles according to each corresponding formula, which isn't hardto figure out, just figure that there are 12 hours needed, divide 360 by 12, then tell your app to

multiply accordingly, and so on.

NOTE: If you haven't yet noticed, when I refer to 'painter', I'm referring to the Graphics Classthat will be use to 'paint' the form. If you aren't a person for analogies, please excuse mine =)

CollapseDim sec As New Matrix()

sec.Translate(1, 1)

8/6/2019 Vb.net Clock

11/13

sec.RotateAt(secAng, New PointF(170, 170))

e.Graphics.Transform = sec

e.Graphics.DrawImage(secBMP, 0, 0)

sec.Dispose()

This snippet makes aMatrix, which before applying the changes to our 'painter', can be

manipulated much more successfully than just the normal Graphics class. First, the matrix is

positioned, rotated at the point necessary to ensure that the hands to the clock do not move off-center, or even off-screen. Then the changes are applied to our 'painter' using

e.Graphics.Transform = sec. After this, the image is drawn onto the form, and theMatrix isdisposed to empty resources correctly.

Because we have three hands on our clock, and all three work similarly, we find that our codetends to stay similar, but with some differences. This is one of those cases.

CollapseDim min As New Matrix()

min.Translate(1, 1)

min.RotateAt(minAng, New PointF(170, 170))

e.Graphics.Transform = min

e.Graphics.DrawImage(minBMP, 0, 0)

min.Dispose()

Note that the code is the same except for the Image, angle and name, etc. Not much explanationhere. Just a repeat of the last snippet, a change here and there.

CollapseDim hour As New Matrix()

hour.Translate(0, 0)

hour.RotateAt(hourAng, New PointF(170, 170))

e.Graphics.Transform = hour

e.Graphics.DrawImage(hourBMP, 44, 44)

hour.Dispose()

Here is where it changes. We do everything the same except forwhere the image is plotted. For

some reason, If you plot the image at the normal point, it causes it to be off-center, the best pointfor it is at (44,44).

8/6/2019 Vb.net Clock

12/13

Almost Done!

Now that our work-bearing procedures are made, we need a way to initiate them.

Add the Timer tick handler to get this all going.

CollapsePrivate Sub Timer1_Tick(ByVal sender As System.Object, _ByVal e As System.EventArgs) Handles Timer1.TickMe.Refresh()End Sub

OK, wait. Just refresh the form? Refreshing the form causes it to repaint itself. This calls our

OnPaint handler which handles all of our duties. So, let's see if this works. Run the form, the

clock should be blank for a split-second, then a picture is seen. More like a home-made picture.=)

Now We're Finished

If you did everything correct, your watch should look like this.

Recap

8/6/2019 Vb.net Clock

13/13

Well, that was different. A simple sounding subject made hard with the challenge to do as muchof it at runtime and/or from scratch. A matrix can be used to paint the form. Some lifeless images

can be breathed into, and a normal form with NO controls at all can be made to look like aprofessional-made user control. For once, you can get something out of nothing. That's the

beauty of programming.