And to expand on the point that context units can be anything: they don't
even have to be numbers. Here's drawing a horizontal line from today to
tomorrow.
today = Dates.today()
tomorrow = today + Dates.Day(1)
compose(context(units=UnitBox(today, 0, Dates.Day(1), 1)),
line([(today, 0.5), (tomorrow, 0.5)]), stroke("black"))
On Thursday, March 12, 2015 at 12:14:28 AM UTC-7, Daniel Jones wrote:
>
>
> It can actually actually work both ways: cx and cy give "context units",
> which by default are between 0 and 1, and go from left-to-right and
> top-to-bottom, but can be redefined to be anything.
>
> So, this draws a line from the top-left to the bottom-right.
> compose(context(), line([(0cx,0cy), (1cx,1cy)]), stroke("black"))
>
> But I can change the units in the context, it draws a line from the
> bottom-left to top-right.
> compose(context(units=UnitBox(0,1,1,-1)), line([(0cx,0cy), (1cx,1cy)]),
> stroke("black"))
>
> UnitBox defines a new coordinate system in which the top-left corner is
> (0, 1), and the context is 1 unit wide and 1 unit tall, but the height is
> given as "-1", which somewhat unintuitively flips the orientation of the
> units.
>
> If you look at the bottom of "coord.jl" in Gadfly, you'll see how the
> coordinate system for the plot gets set up:
>
> context(units=UnitBox(
> coord.xflip ? xmax : xmin,
> coord.yflip ? ymin : ymax,
> coord.xflip ? -width : width,
> coord.yflip ? height : -height,
> leftpad=xpadding,
> rightpad=xpadding,
> toppad=ypadding,
> bottompad=ypadding),
>
>
>
>
>
>
> On Wednesday, March 11, 2015 at 10:33:35 PM UTC-7, nanaya tachibana wrote:
>>
>> I wanted to contribute to Gadfly.jl and I started from looking into
>> bar.jl.
>> I found that the value cy of Measure in Gadfly.jl increases from bottom
>> to top, but it increases from top to bottom in Compose.jl.
>> What makes Measure work in that way?
>>
>> I really appreciate any help you can provide.
>>
>>
