libgsh 1.2.0

Graphical Shell server SDK library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

use crate::shared::protocol::frame::Segment;

pub fn full_frame_segment(
    full_frame_data: &[u8],
    frame_width: usize,
    frame_height: usize,
) -> Vec<Segment> {
    vec![Segment {
        x: 0,
        y: 0,
        width: frame_width as u32,
        height: frame_height as u32,
        data: full_frame_data.to_vec(),
    }]
}

/// A function to optimize a frame segments for transmission.
/// Identifying what partial (rectangle-area) updates are needed to be sent to the client compared to the previous frame.
pub fn optimize_segments(
    full_frame_data: &[u8],
    frame_width: usize,
    frame_height: usize,
    prev_frame: &mut Vec<u8>,
    pixel_bytes: usize,
) -> Vec<Segment> {
    const MIN_SEGMENT_ROWS: usize = 4; // Minimum segment size in rows
    const MAX_SEGMENT_COUNT: usize = 50; // Maximum number of segments to send
    let mut optimized_segments = Vec::new();
    let mut current_segment: Option<Segment> = None;

    // Compare the new segment with the previous one and find differences
    for y in 0..frame_height {
        let start = y * frame_width * pixel_bytes;
        let end = start + frame_width * pixel_bytes;
        if let Some(prev_frame) = prev_frame.get(start..end) {
            if *prev_frame != full_frame_data[start..end] {
                let segment_data = full_frame_data[start..end].to_vec();
                if let Some(ref mut segment) = current_segment {
                    // Extend the current segment if it's contiguous
                    if segment.y + segment.height as i32 == y as i32
                        && segment.width as usize == frame_width
                    {
                        segment.height += 1;
                        segment.data.extend(segment_data);
                    } else {
                        if optimized_segments.len() + 1 > MAX_SEGMENT_COUNT {
                            // If we exceed the maximum segment count, return the full frame as one segment
                            return full_frame_segment(full_frame_data, frame_width, frame_height);
                        }
                        // Push the current segment if it has enough rows
                        if segment.height as usize >= MIN_SEGMENT_ROWS {
                            optimized_segments.push(segment.clone());
                        }
                        // Start a new segment
                        *segment = Segment {
                            x: 0,
                            y: y as i32,
                            width: frame_width as u32,
                            height: 1,
                            data: segment_data,
                        };
                    }
                } else {
                    // Start the first segment
                    current_segment = Some(Segment {
                        x: 0,
                        y: y as i32,
                        width: frame_width as u32,
                        height: 1,
                        data: segment_data,
                    });
                }
            }
        } else {
            // If the previous frame is not available, send the entire row
            let segment_data = full_frame_data[start..end].to_vec();
            if let Some(ref mut segment) = current_segment {
                if segment.y + segment.height as i32 == y as i32
                    && segment.width as usize == frame_width
                {
                    segment.height += 1;
                    segment.data.extend(segment_data);
                } else {
                    if optimized_segments.len() + 1 > MAX_SEGMENT_COUNT {
                        // If we exceed the maximum segment count, return the full frame as one segment
                        return full_frame_segment(full_frame_data, frame_width, frame_height);
                    }
                    if segment.height as usize >= MIN_SEGMENT_ROWS {
                        optimized_segments.push(segment.clone());
                    }
                    *segment = Segment {
                        x: 0,
                        y: y as i32,
                        width: frame_width as u32,
                        height: 1,
                        data: segment_data,
                    };
                }
            } else {
                current_segment = Some(Segment {
                    x: 0,
                    y: y as i32,
                    width: frame_width as u32,
                    height: 1,
                    data: segment_data,
                });
            }
        }
    }

    // Push the last segment if it exists and has enough rows
    if let Some(segment) = current_segment {
        optimized_segments.push(segment);
    }

    // Update the previous frame with the new data
    prev_frame.resize(full_frame_data.len(), 0);
    prev_frame.copy_from_slice(full_frame_data);

    optimized_segments
}

// fn find_diffs(
//     full_frame_data: &[u8],
//     prev_frame: &[u8],
//     width: usize,
//     height: usize,
//     pixel_bytes: usize,
// ) -> Vec<(usize, usize, usize, usize)> {
//     let mut diffs = Vec::new();

//     for y in 0..height {
//         for x in 0..width {
//             let start = (y * width + x) * pixel_bytes;
//             let end = start + pixel_bytes;
//             if full_frame_data[start..end] != prev_frame[start..end] {
//                 diffs.push((x, y, pixel_bytes, 1));
//             }
//         }
//     }

//     diffs
// }

// fn optimal_diff_groups(
//     diffs: &[(usize, usize, usize, usize)],
//     width: usize,
//     height: usize,
// ) -> Vec<(usize, usize, usize, usize)> {
//     let mut groups = Vec::new();
//     let mut current_group = None;

//     for &(x, y, pixel_bytes, height) in diffs {
//         if let Some((group_x, group_y, group_width, group_height)) = current_group {
//             if x == group_x && y == group_y + group_height {
//                 current_group = Some((group_x, group_y, group_width, group_height + height));
//             } else {
//                 groups.push((group_x, group_y, group_width, group_height));
//                 current_group = Some((x, y, pixel_bytes, height));
//             }
//         } else {
//             current_group = Some((x, y, pixel_bytes, height));
//         }
//     }

//     if let Some((group_x, group_y, group_width, group_height)) = current_group {
//         groups.push((group_x, group_y, group_width, group_height));
//     }

//     groups
// }