| // Licensed to Apache Software Foundation (ASF) under one or more contributor |
| // license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright |
| // ownership. Apache Software Foundation (ASF) licenses this file to you 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 axes |
| |
| // label.go contains code that calculates the positions of labels on the axes. |
| |
| import ( |
| "fmt" |
| "image" |
| |
| "github.com/mum4k/termdash/align" |
| "github.com/mum4k/termdash/private/alignfor" |
| ) |
| |
| // Label is one text label on an axis. |
| type Label struct { |
| // Label content. |
| Text string |
| |
| // Position of the label within the canvas. |
| Pos image.Point |
| } |
| |
| // yLabels returns labels that should be placed next to the Y axis. |
| // The labelWidth is the width of the area from the left-most side of the |
| // canvas until the Y axis (not including the Y axis). This is the area where |
| // the labels will be placed and aligned. |
| // Labels are returned with Y coordinates in ascending order. |
| // Y coordinates grow down. |
| func yLabels(graphHeight, labelWidth int, stringLabels []string) ([]*Label, error) { |
| if min := 2; graphHeight < min { |
| return nil, fmt.Errorf("cannot place labels on a canvas with height %d, minimum is %d", graphHeight, min) |
| } |
| if min := 0; labelWidth < min { |
| return nil, fmt.Errorf("cannot place labels in label area width %d, minimum is %d", labelWidth, min) |
| } |
| |
| var labels []*Label |
| for row, l := range stringLabels { |
| label, err := rowLabel(row, l, labelWidth) |
| if err != nil { |
| return nil, err |
| } |
| |
| labels = append(labels, label) |
| } |
| |
| return labels, nil |
| } |
| |
| // rowLabel returns one label for the specified row. |
| // The row is the Y coordinate of the row, Y coordinates grow down. |
| func rowLabel(row int, label string, labelWidth int) (*Label, error) { |
| // The area available for the label |
| ar := image.Rect(0, row, labelWidth, row+1) |
| |
| pos, err := alignfor.Text(ar, label, align.HorizontalRight, align.VerticalMiddle) |
| if err != nil { |
| return nil, fmt.Errorf("unable to align the label value: %v", err) |
| } |
| |
| return &Label{ |
| Text: label, |
| Pos: pos, |
| }, nil |
| } |
| |
| // xLabels returns labels that should be placed under the X axis. |
| // Labels are returned with X coordinates in ascending order. |
| // X coordinates grow right. |
| func xLabels(yEnd image.Point, graphWidth int, stringLabels []string, cellWidth int) ([]*Label, error) { |
| var ret []*Label |
| |
| length, index := paddedLabelLength(graphWidth, LongestString(stringLabels), cellWidth) |
| |
| for x := yEnd.X + 1; x <= graphWidth && index < len(stringLabels); x += length { |
| ar := image.Rect(x, yEnd.Y, x+length, yEnd.Y+1) |
| pos, err := alignfor.Text(ar, stringLabels[index], align.HorizontalCenter, align.VerticalMiddle) |
| if err != nil { |
| return nil, fmt.Errorf("unable to align the label value: %v", err) |
| } |
| |
| l := &Label{ |
| Text: stringLabels[index], |
| Pos: pos, |
| } |
| index += length / cellWidth |
| ret = append(ret, l) |
| } |
| |
| return ret, nil |
| } |
| |
| // paddedLabelLength calculates the length of the padded label and |
| // the column index corresponding to the label. |
| // For example, the longest label's length is 5, like '12:34', and the cell's width is 3. |
| // So in order to better display, every three cells will display a label, |
| // the label belongs to the middle column of the three columns, |
| // and the padded length is 3*3, which is 9. |
| func paddedLabelLength(graphWidth, longest, cellWidth int) (l, index int) { |
| l, index = 0, 0 |
| for i := longest/cellWidth + 1; i < graphWidth/cellWidth; i++ { |
| if (i*cellWidth-longest)%2 == 0 { |
| l = i * cellWidth |
| index = i / 2 |
| break |
| } |
| } |
| return |
| } |