   ## Different Scaled Mask/Masked Layers: Find Equiv Zoom & Pan

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### Different Scaled Mask/Masked Layers: Find Equiv Zoom & Pan

Recently I came across someone asking for some unique help. He was using two different scales in the same mask set. One mask set was smaller than the other. He knew the information for size and position of the smaller mask set and the size and position of the mask for the larger mask set. He wanted to know how to determine the size and position of the larger mask set's image layer such that it displayed the image of the smaller mask set exactly the same ... except that it was larger. The masks used fit to frame scale while the image layers used fill frame scale.

This is what is being attempted: http://fenimorephotovideos.com/ImagesMi ... skSets.jpg

The size and position of the two mask layers and the masked layer of the small mask set are known. How do you find the size and position of the other masked layer?

So, this is additional information for the scenario. One masked set is located to the upper left of the other and is fairly small. The second mask set is located to the lower right of the first set and shows a larger version of the smaller image. Both images are masked in such a way that only a portion of the actual image is displayed. However, each have exactly the same area displayed. See the image in the link above. The masks use a scale of fit to frame while the image layers use fill frame scaling.

The Scenario: http://fenimorephotovideos.com/ImagesMi ... Images.jpg

There are two issues associated with this scenario.
Issue 1: what zoom value for the larger image is required such that it scales to its mask like the smaller image layer scales to its mask?
Issue 2: how is the larger image positioned within its mask to match the smaller image's display within its mask?

The first thing that is required is to identify what setup is being used and the information that is being sought.

SETUP.
• MASK, Small. Aspect = 800:1200; Scale = Fit to Frame; Zoom = 25, 25; Pan = -35, -30
• IMAGE, Small. Aspect = 800:1200; Scale = Fill Frame; Zoom = 12, 12; Pan = -36, –29
• MASK, Large. Aspect = 800:1200; Scale = Fit to Frame; Zoom = 60, 60; Pan =25, 10
• IMAGE, Large. Aspect = 800:1200; Scale = Fill Frame; Zoom = ?, ?; Pan = ?, ?

So, what is being sought are the larger image's zoom and position settings. Since the mask and image layers possess different scales, the sizing for each is a bit of a problem to figure out (as you may have discovered). Most of us would have no clue how to address this kind of situation. Mainly that is because it is not a situation that appears very often. Most of those who are considered experts have probably run into this situation at one time or another. However, we usually just make sure our workflow avoids this kind of situation. That's because when the layer and mask share the same scale and aspect, size and position calculations are considerably simplified.

Sometimes, however, a situation may arise where there is a need to use different scales. When that happens, the following information may be of assistance.

SUPPORTING INFORMATION
1) EQUATIONS. The following link is to a webpage that contains equations that are very important to addressing the described situation.

http://fpvp.wordpress.com/layer-equations/

These are the relevant equations for all layers at any aspect. However, the equations of interest here are those for the layer's width and height. You need that information (it is important). ProShow does not, at this time, provide this information anywhere. If that information is needed, manual calculations are required.

2) PROSHOW SCALES. This article may be of interest:

http://fpvp.wordpress.com/proshow-discussions/

(read all of sub-articles to that link). Of interest because it explains how a layer is scaled (at least to my understanding). It forms the basis of understanding much of how ProShow does its magic.

3) OTHER TUTORIALS. These tutorials may help too:

http://fenimorephotovideos.com/Tutorials.html

They cover a number of issues on how to use ProShow.

DISCUSSION.
With the specific setup given above, the first thing to do is to find each layer's width and height. Use the equations link above for the appropriate equation to use.

1) Find Each Known Layer's Width and Height.
These values are calculated as follows for a 2:3 aspect layer:

1a) For a zoom of 25, 25 and a scale of fit to frame: 9.375, 25.
1b) For a zoom of 60, 60 and a scale of fit to frame: 22.5, 60.
1c) For a zoom of 12, 12 and a scale of fill frame: 12, 32.

2) Find the Width and Height of the Unknown Layer.
ProShow works on proportions ... so, once the width and height for each of the three given layers above has been calculated, the width and height for the larger image layer can be calculated.

2a) Fit To Frame and Zoom. A layer using a fit to frame scale and which has an aspect that's smaller than the slide's aspect has a height controlled by the Zoom-Y. That is because the layer has been normalized along the vertical axis (that is, the layer at 100% zoom has the same height as the slide).
2b) Fill Frame and Zoom. For the same layer using a fill frame scale, the layer's width is determined by Zoom-X. In this case, the layer's width at 100% zoom is 100% of the slide's width. This is important information to know.
2c) Change in Width, Small Mask Set. Knowing that, the next step is to determine the change in width for the image layer relative to its mask layer. We know that the small image layer has a width of 12 while its mask layer has a width of 9.375. The image layer's size difference from its mask is found by the following:

(Image Width - Mask Width)/Mask Width = change in size. Now, after substituting the actual values into the equation, we arrive at the following:

(12 - 9.375)/9.375 = 0.280

2d) Zoom for Large Mask Set. The information just calculated allows the us to find the larger image's size. We know that the large mask has a width of 22.5 and now we also know the amount of proportional change that will give us the larger layer's width. So, the following relationship is used:

Mask Width + (Mask Width times change amount) = Layer Width. Now, the mask layer's width and the just calculated change amount are substituted into this equation. That gives the following:

22.5 + (22.5*0.28) = 28.8

Since the layer width is determined by the layer's zoom setting for a fill frame scaled layer that has an aspect that is smaller than the slide's aspect, 28.8 is the image layer's zoom setting as well. So, that gives the large image a zoom of 28.8, 28.8.

2e) Large Layer's width, height, and zoom. When we large layer's zoom values, we can substitute this information into the equations for the layer's width and height. The values we were missing are now known as follows:

Zoom = 28.8, 28.8; Width and Height = 28.8, 76.8
(note that 60 + (60*0.28) = 60 + 16.8 = 76. 3) Position Settings For the Large Image Layer.

3a) Default Position. As for the pan settings, each layer of the mask set can share the same pan values despite having different scales. That is because the position, or pan setting is referenced from layer center, always.
3b) Offset Position. When the smaller image layer is offset from its mask's center, what is the new associated pan setting values for the larger image layer relative to its mask layer's position? The answer is dependent upon the change in size between the smaller and larger image layer's. So, we need to know the change is zoom setting for the layer's width or height. Because the two layers have already been normalized to the slide and they share the scale, we just calculate the change in size for each. This then correlates to a change in the scale of the pan setting as well.
3b1) We know the small layer's width and height is 12, 32 and the larger layer's width and height is 28.8, 76.8.

• The width difference then is 28.8/12 = 2.4.
• For the height, it's the same result: 76.8/32=2.4.

So, for every 1% change in the small image layer's offset from the small mask layer's position, the large image layer has an offset of 2.4% change from the large mask layer's position.
3b2) With that in mind, the offset of the small image layer from its mask's position is

-36 - (-35) = -1 (X),
-29 - (-30) = 1 (Y)

or a change of -1,1. Therefore, the offset of the large image layer from it's mask is

25 + (2.4*(-1)) = 22.6 (X),
10 + (2.4*1) = 12.4 (Y),

or a pan setting of 22.6, 12.4.

CONCLUSIONS/RESULTS.

The small mask set information:
• MASK: Aspect = 800:1200; Scale = Fit to Frame; Zoom = 25, 25; Pan = -35, -30. Width, Height = 9.375, 25.
• IMAGE: Aspect = 800:1200; Scale = Fill Frame; Zoom = 12, 12; Pan = -36, –28; Width, Height = 12, 32.

The large mask set information:
• MASK: Aspect = 800:1200; Scale =Fit to Frame; Zoom = 60, 60; Pan = 25, 10; Width, Height = 22.5, 60.
• IMAGE: Aspect = 800:1200; Scale = Fill Frame; Zoom = 28.8, 28.8; Pan = 22.6, 12.4; Width, Height = 28.8, 76.8

So, when given the settings for two masks using fit to frame scale and one masked layer, we calculated the size of the other (unknown) masked layer and its position such that the portion of the image displayed in the larger mask set looks exactly the same as the displayed image in the small mask set ... just larger. The equations for a layer's width and height were obtained from from the link to the equations chart on the equations webpage.

This is a Demo using 2 Different Scale types: https://www.youtube.com/watch?v=t07XdpbbIxc

Have fun exploring!

Dale

Last edited by im42n8 on Mon Mar 02, 2015 9:44 am, edited 4 times in total.
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### Re: Mask & Masked Layers Use Different Scales: Find Zoom & P

This was amazing and helpful. Thank You, Dale!

Happy Holidays!

~Betty

Valued Member
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### Re: Mask & Masked Layers Use Different Scales: Find Zoom & P

Dale,
Thank You!
Merry Christmas and Happy New Year 2015!
Frank  Posts: 3745
Joined: Thu Aug 17, 2006 11:21 am
Location: Parker, CO

### Re: Mask & Masked Layers Use Different Scales: Find Zoom & P

Happy Holidays to you to Betty and Frank! Hope you found the tutorial interesting and useful. You just never know when that information might come in handy.

We got several inches of SNOW today! Looks like we might have a White Christmas here!

Dale
What's New: Tools for ProShow: v11.42a Access ProShow capabilities Photodex doesn't provide (For PSG & PSP).
FPVP Blog "Making the Difficult Easier," FPVP News