Zoom Stack

The zoom stack supports navigation in time by storing previously displayed time intervals. You can restore these time intervals when it is necessary. Keyboard or mouse navigation is quite intuitive without detailed knowledge of the zoom stack. Nevertheless, an explanation is given below for the sake of complete reference.

Consider a trace file spanning the time from 0 to 100 seconds. When the first View is opened the zoom stack looks like this:

0:(0;100)(50;100)

Each stack entry has the syntax (<start>;<stop>)(<center>;<width>). Zooming in using Zoom In  (I), magnifies the Chart by a factor of 2 around the current center. In the above example, the center is at 50 seconds. Therefore, zooming in twice using the I shortcut key will result in the following stack. You can see that a stack level is created for each action performed. On pressing Ctrl+Right twice, the time frame of the Chart is moved to the right by two window sizes:

State of the Zoom Stack - Zoomed In Twice:

3:(55;65)(60;10)
2:(50;70)(60;20)
1:(40;80)(60;40)
0:(0;100)(50;100)

For example, here is the original state of the Zoom Stack:

State of the Zoom Stack - Moved Two Window Sizes to the Right: 

5:(75;85)(80;10)
4:(65;75)(70;10) 3:(55;65)(60;10) 2:(50;70)(60;20) 1:(40;80)(60;40) 0:(0;100)(50;100)

Taking this Zoom Stack as an example, see the differences between Back (B), Zoom Out (O) and Zoom Up (U) explained below.

Back (B): When you press B in the original state, one level of the stack pops out and the previous time frame is displayed:

State of the Zoom Stack after Back (B):

4:(65;75)(70;10)
3:(55;65)(60;10)
2:(50;70)(60;20)
1:(40;80)(60;40)
0:(0;100)(50;100)

Zoom Out (O): Using O in the original state of the Zoom Stack lowers the magnification (doubles the width) and pushes a new item on the stack. Zooming out using O in the original state results in the stack as shown below:

State of the Zoom Stack after Zoom Out (O):

6:(70;90)(80;20)
5:(75;85)(80;10)
4:(65;75)(70;10)
3:(55;65)(60;10)4
2:(50;70)(60;20)
1:(40;80)(60;40)
0:(0;100)(50;100)

Zoom Up (U): The resultant zoom after using U is a little more complicated. Pressing U keeps the current center and uses the magnification from before the latest zoom in (which is the change from level 2 to 3 in the original state) and to clear the stack up to and including the last zoom in found. In this example the current center is 80 and the width from stack level 2, which is 20, is used:

State of the Zoom Stack after Zoom Up (U):

2:(70;90)(80;20)
1:(40;80)(60;40)
0:(0;100)(50;100)

Reset (R): Reset clears the stack and pushes one entry covering the full time range of the trace file.

For more complete information about compiler optimizations, see our Optimization Notice.