Changelog

Source: NEWS.md

Retina 0.1.0

Core Infrastructure

• Added Image R6 class backed by OpenCV cv::Mat / cv::UMat via cpp11.
• Image$new() constructs from a file path or an R array (with colorspace and depth arguments).
• Image$write() saves to file. Image$copy() produces a deep copy.
• Image$plot() and Image$to_native_raster() render images for display.
• Image$to_gpu() / Image$to_cpu() transfer between CPU and GPU buffers.
• dim.Image() returns c(nrow, ncol, nchan).

Depth & Color Space

• Image$convert_depth() / Image$convert_depth_() and Image$to_array() convert bit depth and export pixel data as R arrays.
• Image$convert_color() / Image$convert_color_() converts between color spaces. Convenience shortcuts: $to_gray(), $to_bgr(), $to_hsv(), $to_lab().

Statistics

• Image$mean(), $sd(), $var(), $min(), $max(), $sum(), $median(), $quantile() compute per-channel statistics.
• S3 methods mean.Image, sd.Image, var.Image, min.Image, max.Image, sum.Image, median.Image, quantile.Image are registered.

Arithmetic & Bitwise

• Image$add() / $add_(), $subtract() / $subtract_(), $multiply() / $multiply_(), $divide() / $divide_().
• Image$absdiff() / $absdiff_(), $add_weighted() / $add_weighted_().
• Image$bitwise_and() / $bitwise_and_(), $bitwise_or() / $bitwise_or_(), $bitwise_xor() / $bitwise_xor_(), $bitwise_not() / $bitwise_not_().
• Operator overloads: +, -, *, /, bitwAnd(), bitwOr(), bitwXor(), bitwNot().

Filtering

• Image$blur() / $blur_() — box filter.
• Image$gaussian_blur() / $gaussian_blur_() — Gaussian filter.
• Image$median_blur() / $median_blur_() — median filter.
• Image$bilateral_filter() / $bilateral_filter_() — edge-preserving smooth.

Edge Detection

• Image$sobel() / $sobel_(), $laplacian() / $laplacian_() — gradient operators.
• Image$canny() / $canny_() — Canny edge detector.

Morphology

• Image$morph() / $morph_() — erode, dilate, open, close, gradient, tophat, blackhat operations with custom kernel support.

Geometric Transforms

• Image$resize() / $resize_(), $rotate() / $rotate_(), $flip() / $flip_(), $crop() / $crop_().
• Image$warp_affine() / $warp_affine_() — apply a 2×3 affine matrix.
• Image$warp_perspective() / $warp_perspective_() — apply a 3×3 homography.
• Matrix constructors: affine_translate(), affine_scale(), affine_shear(), affine_rotate(), affine_from_points(), perspective_from_points().

Channel Operations

• split_channels() decomposes a multi-channel image into a named list of single-channel images.
• merge_channels() reassembles from a named list.

Pixel Access

• [.Image reads a single pixel (named vector), a single channel (scalar), or a rectangular region (new Image). Uses 1-based [row, col] indexing.
• [<-.Image writes a single pixel, single channel, or rectangular region.

Image Construction Utilities

• Image$fill(), Image$zeros(), Image$ones() — filled constructors.
• Image$randu(), Image$randn() — random image constructors.
• Image$border() / $border_() — add border padding.
• Image$tile() / $tile_() — tile image N×M times.
• Image$set_to() / $set_to_() — set all or masked pixels to a scalar.
• concatenate() — horizontal or vertical image stacking.

Thresholding

• Image$threshold() / $threshold_() — global threshold with 5 types and 17 ImageJ auto-threshold methods.
• Image$adaptive_threshold() / $adaptive_threshold_() — local mean/Gaussian threshold (CV_8U only).
• Image$in_range() / $in_range_() — per-channel range mask.
• autothreshold_value() — returns computed threshold value without modifying the image.

Drawing

• Image$draw_line() / $draw_line_(), $draw_arrow() / $draw_arrow_().
• Image$draw_rectangle() / $draw_rectangle_(), $draw_circle() / $draw_circle_().
• Image$draw_ellipse() / $draw_ellipse_(), $draw_arc() / $draw_arc_().
• Image$draw_polyline() / $draw_polyline_(), $fill_poly() / $fill_poly_().
• Image$draw_text() / $draw_text_().
• col2bgr() converts R color names / hex strings to BGR(A) numeric vectors.
• get_text_size() measures text bounding box without drawing.