termdash/private/draw/vertical_text.go

121 lines
3.4 KiB
Go

// Copyright 2019 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package draw
// vertical_text.go contains code that prints UTF-8 encoded strings on the
// canvas in vertical columns instead of lines.
import (
"fmt"
"image"
"github.com/mum4k/termdash/cell"
"github.com/mum4k/termdash/private/canvas"
)
// VerticalTextOption is used to provide options to Text().
type VerticalTextOption interface {
// set sets the provided option.
set(*verticalTextOptions)
}
// verticalTextOptions stores the provided options.
type verticalTextOptions struct {
cellOpts []cell.Option
maxY int
overrunMode OverrunMode
}
// verticalTextOption implements VerticalTextOption.
type verticalTextOption func(*verticalTextOptions)
// set implements VerticalTextOption.set.
func (vto verticalTextOption) set(vtOpts *verticalTextOptions) {
vto(vtOpts)
}
// VerticalTextCellOpts sets options on the cells that contain the text.
func VerticalTextCellOpts(opts ...cell.Option) VerticalTextOption {
return verticalTextOption(func(vtOpts *verticalTextOptions) {
vtOpts.cellOpts = opts
})
}
// VerticalTextMaxY sets a limit on the Y coordinate (row) of the drawn text.
// The Y coordinate of all cells used by the vertical text must be within
// start.Y <= Y < VerticalTextMaxY.
// If not provided, the height of the canvas is used as VerticalTextMaxY.
func VerticalTextMaxY(y int) VerticalTextOption {
return verticalTextOption(func(vtOpts *verticalTextOptions) {
vtOpts.maxY = y
})
}
// VerticalTextOverrunMode indicates what to do with text that overruns the
// VerticalTextMaxY() or the width of the canvas if VerticalTextMaxY() isn't
// specified.
// Defaults to OverrunModeStrict.
func VerticalTextOverrunMode(om OverrunMode) VerticalTextOption {
return verticalTextOption(func(vtOpts *verticalTextOptions) {
vtOpts.overrunMode = om
})
}
// VerticalText prints the provided text on the canvas starting at the provided point.
// The text is printed in a vertical orientation, i.e:
// H
// e
// l
// l
// o
func VerticalText(c *canvas.Canvas, text string, start image.Point, opts ...VerticalTextOption) error {
ar := c.Area()
if !start.In(ar) {
return fmt.Errorf("the requested start point %v falls outside of the provided canvas %v", start, ar)
}
opt := &verticalTextOptions{}
for _, o := range opts {
o.set(opt)
}
if opt.maxY < 0 || opt.maxY > ar.Max.Y {
return fmt.Errorf("invalid VerticalTextMaxY(%v), must be a positive number that is <= canvas.width %v", opt.maxY, ar.Dy())
}
var wantMaxY int
if opt.maxY == 0 {
wantMaxY = ar.Max.Y
} else {
wantMaxY = opt.maxY
}
maxCells := wantMaxY - start.Y
trimmed, err := TrimText(text, maxCells, opt.overrunMode)
if err != nil {
return err
}
cur := start
for _, r := range trimmed {
cells, err := c.SetCell(cur, r, opt.cellOpts...)
if err != nil {
return err
}
cur = image.Point{cur.X, cur.Y + cells}
}
return nil
}