Function Rotate(Angle As Float) As Image

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Askjerry
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Function Rotate(Angle As Float) As Image

Post by Askjerry » Tuesday 27th April 2021 2:32am

I see that there is a function to rotate an image... I just can't seem to figure it out.

Lets say that I have an image called "round_thing" and I make a button... obviously when I click it I will get...

Code: Select all

Public Sub Button1_Click()
 ' --- What goes here????
End
What I want to do is something like round_thing.rotate(5) to rotate the image 5 degrees in this case... but I just don't understand where and how to use the function.

Code: Select all

Function Rotate(Angle As Float) As Image
' --- Again... I have no clue.
End
If I get this... I can make some awesome gauges in Inkscape and have the dials rotate as needed.

Thanks,
Jerry

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stevedee
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Re: Function Rotate(Angle As Float) As Image

Post by stevedee » Tuesday 27th April 2021 7:12am

Askjerry wrote:
Tuesday 27th April 2021 2:32am
I see that there is a function to rotate an image...
Take a look at the Image class: https://gambaswiki.org/wiki/comp/gb.qt4/image

Basically .Rotate returns a rotated copy of an image which you will then need to display (i.e. it doesn't just rotate an image directly on the screen)

Maybe something like:-
  imgThisImage = Image.Load(sImageFile)
  PicBox.Image = imgThisImage
...
  imgRotImage = imgThisImage.Rotate(10.0)
  PicBox.Image = imgRotImage
...but I haven't tested this. I've just scratched this out over breakfast!

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Askjerry
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Re: Function Rotate(Angle As Float) As Image

Post by Askjerry » Wednesday 28th April 2021 12:52am

I kinda see where you are getting..
1) There exists an image.
2) It makes a copy into memory.
3) It makes changes to this copy.
4) The copy is loaded into the image box as if it were an image.
5) The user sees the copy which has taken the place of the source image.

If that is the case, we can load the image into a variable... pass it through the routine like a filter with rotate=0.
Then for any other value, repeat the step with the associated angle value.

I get the theory... but still not quite sure how to implement it. The lat time I made a 3D model of a servo and then used a program to animate it... I exported the animation as image so i had SERVO-000.png to SERVO-100.png and simply loaded the image I wanted based on the number 1 to 100. (Using math to pick the image number.) Goofy perhaps... but it worked. I could do that with a transparent png for a gauge... just trying to do it as a rotate because then I could do it without making an animation. But if I can't figure it out... that is always another means to do it.

Thanks,
Jerry

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stevedee
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Re: Function Rotate(Angle As Float) As Image

Post by stevedee » Wednesday 28th April 2021 7:06am

Askjerry wrote:
Wednesday 28th April 2021 12:52am
...I get the theory... but still not quite sure how to implement it. ...
I guess it will depend on what you want the final image to look like, so having a number of pre-made images could be your best approach.

But since you wanted to try .Rotate here are a few more of my 'breakfast scratchings'

Process:-
- Open Gimp and create a new transparent image (I made mine 300 x 300).
- Use the Ellipse selection tool to create a circle, then fill it with white paint.
- Save in your Gambas project folder.
- Add a PictureBox (300x300) and a Button to a Gambas form and write some code:-
Public Sub Form_Open()
  
  PicBox1.Alignment = 3   'central alignment
  PicBox1.Tag = 0.0         'use Tag as a counter
  
End

Public Sub btnRotate_Click()
Dim imgThisImage As Image
Dim imgRotImage As Image

  imgThisImage = Image.Load("Dial.png")
  PicBox1.Image = imgThisImage

  imgRotImage = imgThisImage.Rotate(PicBox1.Tag)
  PicBox1.Image = imgRotImage
 
  Inc PicBox1.Tag
End
Once again, this is a just a breakfast prototype/proof-of-concept.

It looks like the .Rotate is in Radians, but I'll leave you to work out how to scale it.

My simple dial looks like this as Angle is incremented:-
DialRotate.png
DialRotate.png (22.95 KiB) Viewed 1046 times

EDIT:-

I just remembered, use Rad for degrees to radians
imgRotImage = imgThisImage.Rotate(Rad(PicBox1.Tag))

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cogier
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Re: Function Rotate(Angle As Float) As Image

Post by cogier » Wednesday 28th April 2021 2:17pm

Have a look at the following programs on the Gambas Farm: -

An excellent 'example' program Painting 1.0.0
This one uses the Paint Class to redraw the clock Analogue_clock 1.0.0

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Askjerry
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Re: Function Rotate(Angle As Float) As Image

Post by Askjerry » Wednesday 05th May 2021 1:38am

Stevedee: First time I've been on in a bit, I wanted to thank you for the code... it works! I'll need to tinker with it to see if I can dissect it better and get a better feel for it. I did notice that the image is a bit fuzzy as compared to the original image... so I think I will stick to the animation trick of making a series of images... even if it does take a bit more memory and means an image load each time. I've run it so fast that your eyes can't keep up with it and it still ran smoothly... so it may be that it can load just as fast as it can perform the rotational math.

Give Inkscape a try for graphic generation... it is a vector graphics so you have transparency, gradients, etc. Then when you get the image you like, you can export it as a PNG at any resolution you want to make incredibly detailed graphics. As soon as I have a chance, I'll make a demo to show some of the things you can accomplish with this method... hopefully help someone else along the way.

Cogier: I'll take a look at those... thanks!

~ Jerry :D

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stevedee
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Re: Function Rotate(Angle As Float) As Image

Post by stevedee » Wednesday 05th May 2021 8:20am

Askjerry wrote:
Wednesday 05th May 2021 1:38am
...I did notice that the image is a bit fuzzy as compared to the original image... so I think I will stick to the animation trick of making a series of images...

...Give Inkscape a try for graphic generation...
Jerry, you may be interested in a recent post & example by Doctor Watson about fuzzy images, and how using vector graphics is a better approach: https://forum.gambas.one/viewtopic.php?f=4&t=1106

Thanks for the tip on Inkscape. I do quite a bit of photography using RawTherapee to convert RAW to Tiff then edit with Gimp, which can do pretty much most things including convert to many formats, but it may be a little over-blown for some tasks.

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Askjerry
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Re: Function Rotate(Angle As Float) As Image

Post by Askjerry » Sunday 30th May 2021 3:32am

I will look at the link you sent... if I can use SVG natively in Gambas it would be great.
I don't know if you are aware or not, but in the SVG format everything is named... or has a reference. This means that you can tell the file to make changes.

Rather than explain it all, I'll send you to a page I wrote as an experiment... in the sample Gauge, the pointer is named "POINTER" so i can basically tell it to rotate the pointer 45 degrees and it looks great. Have a look and play with these two examples to see what i'm talking about. You can also embed things like button clicks on individual components.

http://askjerry.info/SVG/

Let me know what you think. Again... I'll check out your links.

Thanks,
Jerry

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stevedee
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Re: Function Rotate(Angle As Float) As Image

Post by stevedee » Sunday 30th May 2021 6:51am

Askjerry wrote:
Sunday 30th May 2021 3:32am
...Let me know what you think...
I love both of your gauges Jerry, especially the shadow detail that changes as the dial rotates on this one;
AskJerry.png
AskJerry.png (78.87 KiB) Viewed 457 times

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tincho
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Re: Function Rotate(Angle As Float) As Image

Post by tincho » Tuesday 01st June 2021 6:43pm

Askjerry wrote:
Tuesday 27th April 2021 2:32am
If I get this... I can make some awesome gauges in Inkscape and have the dials rotate as needed.
Hi Jerry,
It is possible to use svg files in the graphic interfaces of gambas in different controls, from buttons to picturebox, the quality is excellent, it has no comparison with a pixel image.
Here is an example that loads your image of the pressure gauge.
If you wish, you can also take a look at tradukisto in gambas farm where i use SVG for icons and other things.
Public Sub Form_Open()
  Dim pic As Picture
  pic = Image.Load("./pg.svg").Stretch(PictureBox1.w, PictureBox1.h).Picture
  PictureBox1.Picture = pic
End
Image
Note: I took the liberty of using your svg image.
Regards
Martin.
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