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geometry.rs
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geometry.rs
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use serde::{Deserialize, Serialize};
use std::arch::wasm32::*;
use std::ptr::addr_of;
#[repr(C)]
#[derive(Serialize, Deserialize, Clone, Copy, Debug)]
pub struct PlotScale {
pub x_offset: f32,
pub y_offset: f32,
pub x_value_range: f32,
pub y_value_range: f32,
pub x_display_range: f32,
pub y_display_range: f32,
}
pub fn transform_point_to_plot_scale(x: f32, y: f32, plot_scale: &PlotScale) -> (f32, f32) {
(
plot_scale.x_offset + x * plot_scale.x_value_range / plot_scale.x_display_range,
plot_scale.y_offset + y * plot_scale.y_value_range / plot_scale.y_display_range,
)
}
pub fn transform_point_to_canvas_scale(x: f32, y: f32, plot_scale: &PlotScale) -> (f32, f32) {
(
((x - plot_scale.x_offset) * plot_scale.x_display_range / plot_scale.x_value_range),
((y - plot_scale.y_offset) * plot_scale.y_display_range / plot_scale.y_value_range),
)
}
// Formula:
// x = x_offset + x * x_value_range / width
// y = y_offset + y * y_value_range / height
#[target_feature(enable = "simd128")]
pub fn simd_transform_point_to_plot_scale(_points: v128, plot_scale: &PlotScale) -> v128 {
// Note: because parameters in PlotScale are arranged
// linearly in memory, we can use pointer to x-related
// params to extract simultaneously both x- and y-related
// params. To do this, the pointer is cast to u64.
unsafe {
// For short x_value_range = xr, y_value_range = yr
// _ranges = [xr, yr, xr, yr]
let _ranges = v128_load64_splat(addr_of!(plot_scale.x_value_range) as *const u64);
// _sizes = [width, height, width, height]
let _sizes = v128_load64_splat(addr_of!(plot_scale.x_display_range) as *const u64);
// For short x_offset = xo, y_offset = yo
// _offsets = [xo, yo, xo, yo]
let _offsets = v128_load64_splat(addr_of!(plot_scale.x_offset) as *const u64);
// x * x_value_range
// [x1 * xr, y1 * yr, x2 * xr, y2 * yr]
let _mul = f32x4_mul(_points, _ranges);
// x * x_value_range / width
// [
// x1 * xr / width,
// y1 * yr / height,
// x2 * xr / width,
// y2 * yr / height
// ]
let _div = f32x4_div(_mul, _sizes);
// x_offset + x * x_value_range / width
// [
// xo + x1 * xr / width,
// yo + y1 * yr / height,
// xo + x2 * xr / width,
// yo + y2 * yr / height
// ]
f32x4_add(_div, _offsets)
}
}