Immutable command structures for drawing operations. More...
#include "epaper/core/geometry.hpp"#include "epaper/core/types.hpp"#include "epaper/graphics/font.hpp"#include <cstdint>#include <string>#include <string_view>
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Classes | |
| struct | epaper::LineCommand |
| Command for drawing a line between two points. More... | |
| struct | epaper::RectangleCommand |
| Command for drawing a rectangle. More... | |
| struct | epaper::CircleCommand |
| Command for drawing a circle. More... | |
| struct | epaper::PointCommand |
| Command for drawing a point (pixel or multi-pixel dot). More... | |
| struct | epaper::TextCommand |
| Command for drawing text. More... | |
Namespaces | |
| namespace | epaper |
Enumerations | |
| enum class | epaper::TextContent { epaper::String , epaper::Number , epaper::Decimal } |
| Content type for text rendering. More... | |
Detailed Description
Immutable command structures for drawing operations.
Defines value types representing drawing commands. Each command is a plain struct (no methods beyond constructors) that encapsulates all parameters needed to perform a drawing operation.
Design Pattern:
Command Pattern (Data-Oriented)
├─ Immutable: All members const or effectively const after construction
├─ Value Semantics: Cheap to copy, no ownership issues
├─ Serializable: POD-like structs (could be written to binary format)
└─ Decoupled: Commands independent of execution (Display handles rendering)
Rationale:
- Separation of Concerns: Command creation (builders) vs execution (Display)
- Testability: Commands can be constructed and validated without hardware
- Serialization: Commands could be logged, queued, or replayed
- Type Safety: Each command type carries exactly the parameters it needs
Lifetime:
- Commands typically stack-allocated and short-lived
- Builder creates command, immediately passed to Display::draw(), then destroyed
- For deferred rendering, commands can be stored in std::vector or queue
Thread Safety:
- Commands are const after construction (inherently thread-safe to read)
- Font pointers must remain valid during command lifetime (borrowed, not owned)
