// 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 }