zest-simulator

zest-simulator is the desktop Platform implementation for the zest GUI framework family.

It renders with tiny-skia into an RGBA pixmap, converts the output to Rgb565, and displays it through embedded-graphics-simulator and SDL2.

The simulator implements zest_core::Platform<Color = Rgb565>.

What it provides

• SimulatorPlatform
• SimulatorPlatformBuilder
• default desktop settings for a 320×240 RGB565 display
• SDL-backed event polling
• touch-style input through mouse press / move / release
• keyboard input mapped into KeyEvent
• mouse-wheel input mapped into EncoderEvent
• dirty-region rendering support
• optional dirty-rectangle overlay output

Defaults

The crate exports these defaults:

• DEFAULT_WIDTH = 320
• DEFAULT_HEIGHT = 240
• DEFAULT_SCALE = 2
• DEFAULT_PIXEL_SPACING = 0
• DEFAULT_POLL_MS = 16

Basic usage

use zest_simulator::SimulatorPlatform;

let platform = SimulatorPlatform::new("demo");

For custom configuration, use the builder:

use embedded_graphics::prelude::Size;
use zest_simulator::SimulatorPlatform;

let platform = SimulatorPlatform::builder("demo")
    .size(Size::new(320, 240))
    .scale(2)
    .pixel_spacing(0)
    .poll_ms(16)
    .show_dirty(true)
    .build();

Input mapping

The simulator maps SDL events into zest-core input types:

• left mouse button down / move / up → TouchEvent
• supported keyboard keys → KeyEvent
• mouse wheel → EncoderEvent

Rendering behavior

The simulator reports clipping and partial-flush support through PlatformCapabilities.

It implements both:

• render_with(...)
• render_with_dirty(...)

When show_dirty(true) is enabled, the simulator outlines dirty rectangles after partial redraws.

Notes

• The simulator is fixed to Rgb565.
• The crate uses std.
• It is intended for desktop development and debugging, not embedded deployment.