Documentation
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Overview ¶
Package position defines position adjustments that control how overlapping geometries are arranged. In ggplot2's grammar, position adjustments are applied after statistical transforms and before final rendering.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type FillSetup ¶ added in v0.0.4
type FillSetup interface {
Setup(allXs, allYs [][]float64)
}
FillSetup is optionally implemented by position adjustments that need a pre-pass over all groups before per-group Adjust calls.
type Name ¶ added in v0.0.4
type Name string
Name identifies a position adjustment type for factory lookup.
type Pos ¶
type Pos interface {
// Adjust modifies (x, y) positions for a single group within a layer.
// groupIdx is the 0-based index of this group, nGroups is the total count.
// width is the available bin width for dodging/stacking calculations.
Adjust(xs, ys []float64, width float64, groupIdx, nGroups int) ([]float64, []float64)
// String returns a human-readable label.
String() string
}
Pos adjusts the positions of geometric elements to handle overlap. Each adjustment receives the raw data coordinates and group metadata, and returns adjusted coordinates.
func Dodge ¶
func Dodge() Pos
Dodge returns a position that shifts groups side by side within each bin. This is the standard adjustment for grouped bar charts.
func Fill ¶ added in v0.0.4
func Fill() Pos
Fill returns a position that stacks groups and normalizes each x-bin to a total of 1.0 (100% stacked bar chart).
Fill is a two-phase adjustment:
- Setup phase: call FillSetup with all groups' (xs, ys) to compute totals.
- Adjust phase: call Adjust for each group in order.
If Setup is not called, Fill behaves like Stack (no normalization).
func Jitter ¶
Jitter returns a position that adds random noise to (x, y) to reduce overplotting. The jitter is reproducible: same data length produces same offsets.
func New ¶ added in v0.0.4
New creates a fresh Pos instance by name. This is used by the build pipeline to create per-panel-layer position instances (avoiding shared state across panels). Returns Identity for unknown names.
func Stack ¶
func Stack() Pos
Stack returns a position that stacks groups vertically. Each group's y-values are offset by the cumulative sum of prior groups at the same x-value.
Stack is stateful: it accumulates offsets across successive Adjust calls. The build pipeline must create a fresh Stack() instance per panel-layer to avoid cross-panel contamination.
type Stacker ¶ added in v0.0.4
type Stacker interface {
AdjustStack(xs, ys []float64, width float64, groupIdx, nGroups int) (adjXs, yMin, yMax []float64)
}
Stacker is optionally implemented by positions that produce stacked output. When implemented, AdjustStack returns (adjustedXs, yMin, yMax) where yMin is the bottom of each bar and yMax is the top. The pipeline uses yMin to set the bar's base coordinate.
Source Files