Overview
The ironrdp-graphics crate provides image processing primitives and compression algorithms used in RDP graphics rendering:
- Color space conversions (RGB ↔ YUV)
- Image compression (RLE, RLGR)
- Bulk compression (ZGFX)
- RemoteFX encoding components (DWT, quantization)
- Bitmap difference calculations
Key Modules
Color Conversion
use ironrdp_graphics::color_conversion::*;
Compression Algorithms
RLE (Run-Length Encoding)
use ironrdp_graphics::rle::*;
pub mod rle {
pub struct Code(u8);
impl Code {
pub const REGULAR_BG_RUN: Self = Self(0x00);
pub const MEGA_MEGA_BG_RUN: Self = Self(0xF0);
// ... other codes
}
}
RLGR (Run-Length Golomb-Rice)
use ironrdp_graphics::rlgr::*;
use ironrdp_pdu::codecs::rfx::EntropyAlgorithm;
pub fn encode(
mode: EntropyAlgorithm,
input: &[i16],
output: &mut [u8]
) -> Result<usize, RlgrError>
ZGFX (Bulk Compression)
use ironrdp_graphics::zgfx::*;
pub struct Decompressor { /* ... */ }
impl Decompressor {
pub fn new() -> Self;
pub fn decompress(&mut self, input: &[u8], output: &mut [u8]) -> Result<usize, ZgfxError>;
}
RemoteFX Components
use ironrdp_graphics::dwt::*;
pub fn encode(input: &mut [i16], temp: &mut [i16]);
pub fn decode(input: &mut [i16], temp: &mut [i16]);
Quantization
use ironrdp_graphics::quantization::*;
use ironrdp_pdu::codecs::rfx::Quant;
pub fn encode(data: &mut [i16], quant: &Quant);
pub fn decode(data: &mut [i16], quant: &Quant);
Subband Reconstruction
use ironrdp_graphics::subband_reconstruction::*;
pub fn encode(ll3: &mut [i16]);
pub fn decode(ll3: &mut [i16]);
RDP 6 Compression
use ironrdp_graphics::rdp6::*;
Image Processing Utilities
use ironrdp_graphics::image_processing::*;
Rectangle Processing
use ironrdp_graphics::rectangle_processing::*;
Bitmap Difference
use ironrdp_graphics::diff::*;
Pointer (Cursor) Handling
use ironrdp_graphics::pointer::*;
RemoteFX Encoding
The crate provides a high-level function for encoding RemoteFX components:
pub fn rfx_encode_component(
input: &mut [i16],
output: &mut [u8],
quant: &ironrdp_pdu::codecs::rfx::Quant,
mode: ironrdp_pdu::codecs::rfx::EntropyAlgorithm,
) -> Result<usize, rlgr::RlgrError>
Component data (must be 4096 elements = 64×64 pixels). Modified in-place during encoding.
Buffer to receive encoded data
Quantization parameters from ironrdp_pdu::codecs::rfx::Quant
Entropy algorithm (RLGR1 or RLGR3)
input.len() != 4096.
Example:
use ironrdp_graphics::rfx_encode_component;
use ironrdp_pdu::codecs::rfx::{Quant, EntropyAlgorithm};
let mut input = vec![0i16; 64 * 64];
let mut output = vec![0u8; 8192];
let quant = Quant::default();
let encoded_size = rfx_encode_component(
&mut input,
&mut output,
&quant,
EntropyAlgorithm::Rlgr3,
)?;
- DWT (Discrete Wavelet Transform)
- Quantization
- Subband reconstruction
- RLGR entropy encoding
Dependencies
This crate depends on:
ironrdp-core - Core traits (public)ironrdp-pdu - PDU structures for codec parameters (public)yuv - YUV color conversion with RDP-specific featuresbit_field, bitflags, bitvec - Bit manipulation
Usage Notes
Performance:
Many functions in this crate operate on large buffers in-place. Pre-allocate buffers and reuse them to avoid repeated allocations:let mut temp = vec![0i16; 64 * 64];
for tile in tiles {
ironrdp_graphics::dwt::encode(&mut tile, &mut temp);
}
Image Formats:
RemoteFX operates on 64×64 tiles in YUV color space. Convert from RGB before encoding:use ironrdp_graphics::color_conversion::rgb_to_yuv;
// Convert RGB tile to YUV
let (y, u, v) = rgb_to_yuv(&rgb_data, width, height);
See Also
