天象馆

用于天文和视频跟踪应用的亚像素精度光点渲染库。

示例图像

示例用法

use planetarium::{Canvas, SpotShape};

// Draw on a square 256x256 pixel canvas.
let mut c = Canvas::new(256, 256);

// Define a round spot shape with diffraction radius of 2.5 pixels.
let shape = SpotShape::default().scale(2.5);

// Add some spots at random positions with varying shape size
// and peak intensity.
let spot1 = c.add_spot((100.3, 130.8), shape, 0.5);
let spot2 = c.add_spot((80.6, 200.2), shape.scale(0.5), 0.9);

// Note: Out of range position coordinates and peak intensities are fine.
//       The resulting spot image is clipped into the canvas rectangle.
//       Peak intensity > 1.0 leads to saturation to the maximum pixel value.
let spot3 = c.add_spot((256.1, 3.5), shape.scale(10.0), 1.1);

// Set the canvas background pixel value.
c.set_background(100);

// Clear the canvas and paint the light spots.
c.draw();

// Access the rendered image data as a linear pixel array.
let image_pixbuf = c.pixels();

// Get pixel at x = 100, y = 200.
let (x, y) = (100, 200);
let (image_width, image_height) = c.dimensions();
let val_x_y = image_pixbuf[(y * image_width + x) as usize];

光点参数调整

在将光点添加到画布后，可以调整一些光点参数，如坐标和峰值强度。

可以通过添加偏移向量来更改光点位置坐标，通过乘以光点照度因子来调整峰值强度。

可以定义自定义世界坐标到画布坐标的转换，这会影响所有光点。

use planetarium::{Canvas, SpotShape, Transform};

// Draw on a square 256x256 pixel canvas.
let mut c = Canvas::new(256, 256);

// Define an elliptic spot shape with diffraction radii of 2.5 x 1.5 pixels
// rotated by 45 degrees counter-clockwise.
let shape1 = SpotShape::default().stretch(2.5, 1.5).rotate(45.0);

// Define an elliptic spot shape by a 2x2 linear transform matrix.
let shape2 = SpotShape::from([[2.0, -0.5], [1.5, 3.0]]);

// Add some spots at random positions with varying shape size
// and peak intensity.
let spot1 = c.add_spot((100.3, 130.8), shape1, 0.5);
let spot2 = c.add_spot((80.6, 200.2), shape2, 0.9);

// Shift the rendered spot positions by applying the relative offset vectors.
// The intrinsic spot position coordinates are immutable.
c.set_spot_offset(spot1, (-34.2, 12.6));
c.set_spot_offset(spot2, (114.2, -73.3));

// Adjust the rendered spot peak intensity by applying the spot illumination factors.
// The intrinsic spot intensities are immutable.
c.set_spot_illumination(spot1, 1.2);
c.set_spot_illumination(spot2, 0.7);

// Query the resulting spot coordinates on the canvas.
let pos1 = c.spot_position(spot1).unwrap();
let pos2 = c.spot_position(spot2).unwrap();

// Query the resulting peak spot intensities.
let int1 = c.spot_intensity(spot1).unwrap();
let int2 = c.spot_intensity(spot2).unwrap();

// Apply a custom world coordinates to canvas coordinates transformation.
c.set_view_transform(Transform::default().translate((13.7, -20.3)));

// Query the resulting spot coordinates on the canvas after
// the view coordinate transformation.
let pos1x = c.spot_position(spot1).unwrap();
let pos2x = c.spot_position(spot2).unwrap();

画布图像导出

Canvas 对象支持将图像导出为 RAW 和 PNG 文件格式。支持 8 位和 16 位 PNG 样本格式。导出为 PNG 格式需要启用默认的 png 功能。

示例图像导出代码

let mut c = Canvas::new(256, 256);

c.set_background(1000);
c.clear();

// Export to a 8-bit gamma-compressed grayscale RAW image.
let raw_8bpp_bytes = c.export_image(ImageFormat::RawGamma8Bpp).unwrap();

// Export to a 10-bit linear light grayscale little-endian RAW image.
let raw_10bpp_bytes = c.export_image(ImageFormat::RawLinear10BppLE).unwrap();

// Export to a 12-bit gamma-compressed grayscale little-endian RAW image.
let raw_12bpp_bytes = c.export_image(ImageFormat::RawLinear12BppLE).unwrap();

// Export to a 8-bit gamma-compressed grayscale PNG image.
let png_8bpp_bytes = c.export_image(ImageFormat::PngGamma8Bpp).unwrap();

// Export to a 16-bit linear light grayscale PNG image.
let png_16bpp_bytes = c.export_image(ImageFormat::PngLinear16Bpp).unwrap();

窗口图像导出

Canvas 对象还支持窗口图像导出。

单个矩形窗口表示画布图像上的感兴趣区域（ROI）。窗口矩形坐标由公共 Window 结构表示。

示例窗口图像导出代码

let c = Canvas::new(256, 256);

// Create a 32x16 pixels window with origin at (100, 150).
let wnd = Window::new(32, 16).at(100, 150);

let fmt = ImageFormat::RawGamma8Bpp;

// Export to the canvas window image bytes.
let raw_window_bytes = c.export_window_image(wnd, fmt).unwrap();

子采样图像导出

Canvas 对象还支持使用独立行和列子采样因子进行子采样图像导出。

只能导出整个画布图像进行子采样。

示例子采样图像导出代码

let c = Canvas::new(256, 256);

let fmt = ImageFormat::RawLinear10BppLE;

// Column (X) and row (Y) subsampling factors
let factors = (4, 2);

// Export to the subsampled canvas image bytes.
let raw_sub_bytes = c.export_subsampled_image(factors, fmt).unwrap();