Declaration
property ScaleY: double;
Description
Specifies the vertical scale factor.
In the common representation A:B (e.g. 1:100000), where A is the size in the image/model, and B the size in the real world.
ScaleY is the B value (100000).
This value and
IO.Params.DpiY determine the displayed values when measuring distances and areas (miMeasureLength, miMeasureRect or miMeasureEllipse in
MouseInteractGeneral) and displaying the ruler (
ShowRulers).
For example, DPI of 100 and Scale of 1 is the same as DPI of 200 at scale of 2, or DPI of 1000 at scale of 0.1.
Default: 1
Measurement and Scaling
Say you have an image that is 100 DPI (dots per inch), so that when it is printed every 100 pixels print out at a size of 1 inch (2.54cm). If TImageEnView.ScaleY/Y=1, using the measurement tool, a length of 100 pixels will naturally display as 1 inch/2.54cm. But what if we have a photograph of an object where 1 inch in the image represents 1 foot (12 inches) in the real world? This would equate to a scale of 1:12, i.e. TImageEnView.ScaleY/Y = 12. Now, when you select 100 pixels, the measurement tool will report 1 foot.
Naturally it will also work the other way. If we have a detailed image that is recorded as 100 DPI (i.e. 100 pixels = 1 inch/25.4 mm), but actually 100 pixels represents 2.5mm, the scale would be 1:0.1, i.e. TImageEnView.ScaleY/Y=0.1 (alternatively, you could set the DPI as 10).
To make it easier, you can use TimageEnView.SetScale. In the first example we would use:
ImageEnView1.SetScale(100, 1, ieuFeet );
And in the second:
ImageEnView1.SetScale(100, 2.5, ieuMillimeters );
Example
// Set a scale factor so that one inch in the photo measures as one mile (i.e. 1:63360)
ImageEnView1.ScaleX := 63360;
ImageEnView1.ScaleY := 63360;
// Set a scale factor so that one cm in the photo measures as one meter (i.e. 1:100)
ImageEnView1.ScaleX := 100;
ImageEnView1.ScaleY := 100;
// Set a scale factor so that one cm in the photo measures as one micron (i.e. 1:1/10000)
ImageEnView1.ScaleX := 0.0001;
ImageEnView1.ScaleY := 0.0001;
See Also

ScaleX
SetScale
MouseInteractGeneral