mirror of https://github.com/mum4k/termdash.git
123 lines
3.8 KiB
Go
123 lines
3.8 KiB
Go
// Copyright 2020 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 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
|
|
}
|