70 lines
1.9 KiB
Go
70 lines
1.9 KiB
Go
package chart
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import (
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"math"
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"github.com/egoist/mygo/ui"
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"git.zacharyzhang.com/ZacharyZhang-NY/MujicaUI/core"
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"git.zacharyzhang.com/ZacharyZhang-NY/MujicaUI/internal"
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)
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// ChartGridOptions configure a ChartGrid.
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type ChartGridOptions struct {
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// X and Y provide grid ticks; either may be nil.
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X, Y *ChartAxisPart
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// Minor subdivides major intervals with fainter lines.
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Minor int
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}
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// ChartGridPart is a grid ready to draw in a plot.
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type ChartGridPart struct {
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opts ChartGridOptions
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major, minor ui.Color
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}
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// ChartGrid draws pixel-aligned major and minor lines.
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func ChartGrid(c *ui.Context, opts ChartGridOptions) ChartGridPart {
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if opts.Minor < 0 || opts.X == nil && opts.Y == nil {
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panic("mujica: ChartGrid needs an axis and Minor ≥ 0")
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}
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for _, a := range []*ChartAxisPart{opts.X, opts.Y} {
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if a != nil && a.opts.Kind == AxisCategory && opts.Minor > 0 {
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panic("mujica: ChartGrid has no minor lines on a category axis")
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}
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}
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k := core.Tokens(c)
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return ChartGridPart{opts: opts, major: k.Border, minor: k.Border.Mix(k.Surface, 0.55)}
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}
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// Draw paints minor lines, then major ones, inside plot.
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func (g ChartGridPart) Draw(p *ui.Painter, plot ui.Rect) {
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for _, a := range []*ChartAxisPart{g.opts.X, g.opts.Y} {
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if a == nil {
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continue
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}
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line := func(v float64, col ui.Color) {
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at := a.Map(plot, v)
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if a.horizontal() {
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internal.RuleV(p, at, plot.Y, plot.Y+plot.H, col)
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} else {
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internal.Rule(p, plot.X, plot.X+plot.W, at, col)
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}
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}
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ticks := a.drawTicks(plot, 4)
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for i := 1; i < len(ticks) && g.opts.Minor > 0; i++ {
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for j := 1; j < g.opts.Minor; j++ {
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f := float64(j) / float64(g.opts.Minor)
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v := ticks[i-1] + (ticks[i]-ticks[i-1])*f
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if a.opts.Kind == AxisLog {
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v = math.Pow(10, math.Log10(ticks[i-1])+(math.Log10(ticks[i])-math.Log10(ticks[i-1]))*f)
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}
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line(v, g.minor)
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}
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}
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for _, t := range ticks {
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line(t, g.major)
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}
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}
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}
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