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// Copyright 2018 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
// rectangle.go draws a rectangle.
import (
"fmt"
"image"
"github.com/mum4k/termdash/cell"
"github.com/mum4k/termdash/private/canvas"
)
// RectangleOption is used to provide options to the Rectangle function.
type RectangleOption interface {
// set sets the provided option.
set(*rectOptions)
}
// rectOptions stores the provided options.
type rectOptions struct {
cellOpts []cell.Option
char rune
}
// rectOption implements RectangleOption.
type rectOption func(rOpts *rectOptions)
// set implements RectangleOption.set.
func (ro rectOption) set(rOpts *rectOptions) {
ro(rOpts)
}
// RectCellOpts sets options on the cells that create the rectangle.
func RectCellOpts(opts ...cell.Option) RectangleOption {
return rectOption(func(rOpts *rectOptions) {
rOpts.cellOpts = append(rOpts.cellOpts, opts...)
})
}
// DefaultRectChar is the default value for the RectChar option.
const DefaultRectChar = ' '
// RectChar sets the character used in each of the cells of the rectangle.
func RectChar(c rune) RectangleOption {
return rectOption(func(rOpts *rectOptions) {
rOpts.char = c
})
}
// Rectangle draws a filled rectangle on the canvas.
func Rectangle(c *canvas.Canvas, r image.Rectangle, opts ...RectangleOption) error {
opt := &rectOptions{
char: DefaultRectChar,
}
for _, o := range opts {
o.set(opt)
}
if ar := c.Area(); !r.In(ar) {
return fmt.Errorf("the requested rectangle %v doesn't fit the canvas area %v", r, ar)
}
if r.Dx() < 1 || r.Dy() < 1 {
return fmt.Errorf("the rectangle must be at least 1x1 cell, got %v", r)
}
for col := r.Min.X; col < r.Max.X; col++ {
for row := r.Min.Y; row < r.Max.Y; row++ {
cells, err := c.SetCell(image.Point{col, row}, opt.char, opt.cellOpts...)
if err != nil {
return err
}
if cells != 1 {
return fmt.Errorf("invalid rectangle character %q, this character occupies %d cells, the implementation only supports half-width runes that occupy exactly one cell", opt.char, cells)
}
}
}
return nil
}
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