gio/layout/context.go -rw-r--r-- 2.0 KiB
layout: automatically add system inset for NewContext

Currently every user needs to manually adjust for system insets.
This is rather verbose and most don't need to deviate from this behavior.

To disable the automatic adjustment, use:

  e.Insets = system.Insets{}
  ctx := layout.NewContext(ops, e)

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
all: make unit.Converter concrete and rename to Metric

An interface for scaling dp and sp is overkill, at least for all
current uses. Make it a concrete struct type, and rename it to the
shorter and more precise Metric.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
all: move Now from system.Config to system.FrameEvent

Then, make layout.Context.Now a field, copied from FrameEvent.Now.

API change:

	gofmt -r 'gtx.Now() -> gtx.Now'

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: change NewContext to take the FrameEvent directly

The layout package imports io/system anyway, so depending on
FrameEvent does not introduce new dependencies.

API change. Use gofmt to adjust your code:

	gofmt -r 'layout.NewContext(a, b, c, d) -> layout.NewContext(a, e)'

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: add Disabled method to Context

This adds a simple method that returns a copy of the Context
with no event queue. Widgets laid out with this Context will
never receive events, and can check whether the event queue
is nil as a hint for whether or not to draw themselves as

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
layout: change Widget to take explicit Context and return explicit Dimensions

Change the definition of Widget from the implicit

        type Widget func()

to the explicit functional

        type Widget func(gtx layout.Context) layout.Dimensions

The advantages are numerous:

- Clearer connection between the incoming context and the output dimensions.
- Returning the Dimensions are impossible to omit.
- Contexts passed by value, so its fields can be exported
and freely mutated by the program.

The only disadvantage is the longer function literals and the many "returns".
What tipped the scales in favour of the explicit Widget variant is that type
aliases can dramatically shorten the literals:

	type (
		C = layout.Context
		D = layout.Dimensions

	widget := func(gtx C) D {

Note that the aliases are not part of the Gio API and it is up to each user
whether they want to use them.

Finally the Go proposal for lightweight function literals,
https://github.com/golang/go/issues/21498, may remove the disadvantage
completely in future.

Context becomes a plain struct with only public fields, and its Reset is
replaced by a NewContext convenience constructor.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout,widget: transpose Constraints to use image.Points for limits

Instead of

    type Contraints struct {
	    Width, Height Constraint


    type Constraints struct {
	    Min, Max image.Point

which leads to simpler use. For example, the Min method is trivally replaced by
the field, and the RigidConstraints constructor is no longer a net win.

API Change. Rewrites:

    gofmt -r 'gtx.Constraints.Min() -> gtx.Constraints.Min'
    gofmt -r 'gtx.Constraints.Width.Min -> gtx.Constraints.Min.X'
    gofmt -r 'gtx.Constraints.Height.Min -> gtx.Constraints.Min.Y'
    gofmt -r 'gtx.Constraints.Height.Max -> gtx.Constraints.Max.Y'
    gofmt -r 'gtx.Constraints.Width.Max -> gtx.Constraints.Max.X'

Signed-off-by: Elias Naur <mail@eliasnaur.com>
all: rename io/event.Key to Tag

Key had an unfortunate association with keyboard input.

This is an API change. The following rewrites were run to fixup
Gio code:

        $ gofmt -r 'pointer.InputOp{Key:a} -> pointer.InputOp{Tag:a}' -w .
        $ gofmt -r 'pointer.InputOp{Key:a, Grab:b} -> pointer.InputOp{Tag:a, Grab:b}' -w .
        $ gofmt -r 'key.InputOp{Key:a} -> key.InputOp{Tag:a}' -w .
        $ gofmt -r 'key.InputOp{Key:a, Focus:b} -> key.InputOp{Tag:a, Focus:b}' -w .
        $ gofmt -r 'event.Key -> event.Tag' -w .

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: replace NewContext with a Queue argument to Context.Reset

We're about to reduce the scope of the Window.Queue by moving it
to FrameEvent. As a consequence, Context can no longer rely on a
Queue constant over its lifetime.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: fix typo

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: fix typos

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: add NewContext, make zero value Contexts useful

While here, unexport the Queue and Config fields. The NewContext
cosntructor is shorter, and there is no reason to expose the fields
to accidental mutation.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
layout: move Context to its own file

Signed-off-by: Elias Naur <mail@eliasnaur.com>