blob: 2ae16349a78dddf25b78305bf606e8cffe408552 (
plain) (
blame)
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
|
Cropping and Scaling algorithm, used in the sh_mobile_ceu_camera driver
=======================================================================
Terminology
-----------
sensor scales: horizontal and vertical scales, configured by the sensor driver
host scales: -"- host driver
combined scales: sensor_scale * host_scale
Generic scaling / cropping scheme
---------------------------------
-1--
|
-2-- -\
| --\
| --\
+-5-- -\ -- -3--
| ---\
| --- -4-- -\
| -\
| - -6--
|
| - -6'-
| -/
| --- -4'- -/
| ---/
+-5'- -/
| -- -3'-
| --/
| --/
-2'- -/
|
|
-1'-
Produced by user requests:
S_CROP(left / top = (5) - (1), width / height = (5') - (5))
S_FMT(width / height = (6') - (6))
Here:
(1) to (1') - whole max width or height
(1) to (2) - sensor cropped left or top
(2) to (2') - sensor cropped width or height
(3) to (3') - sensor scale
(3) to (4) - CEU cropped left or top
(4) to (4') - CEU cropped width or height
(5) to (5') - reverse sensor scale applied to CEU cropped width or height
(2) to (5) - reverse sensor scale applied to CEU cropped left or top
(6) to (6') - CEU scale - user window
S_FMT
-----
Do not touch input rectangle - it is already optimal.
1. Calculate current sensor scales:
scale_s = ((3') - (3)) / ((2') - (2))
2. Calculate "effective" input crop (sensor subwindow) - CEU crop scaled back at
current sensor scales onto input window - this is user S_CROP:
width_u = (5') - (5) = ((4') - (4)) * scale_s
3. Calculate new combined scales from "effective" input window to requested user
window:
scale_comb = width_u / ((6') - (6))
4. Calculate sensor output window by applying combined scales to real input
window:
width_s_out = ((2') - (2)) / scale_comb
5. Apply iterative sensor S_FMT for sensor output window.
subdev->video_ops->s_fmt(.width = width_s_out)
6. Retrieve sensor output window (g_fmt)
7. Calculate new sensor scales:
scale_s_new = ((3')_new - (3)_new) / ((2') - (2))
8. Calculate new CEU crop - apply sensor scales to previously calculated
"effective" crop:
width_ceu = (4')_new - (4)_new = width_u / scale_s_new
left_ceu = (4)_new - (3)_new = ((5) - (2)) / scale_s_new
9. Use CEU cropping to crop to the new window:
ceu_crop(.width = width_ceu, .left = left_ceu)
10. Use CEU scaling to scale to the requested user window:
scale_ceu = width_ceu / width
S_CROP
------
If old scale applied to new crop is invalid produce nearest new scale possible
1. Calculate current combined scales.
scale_comb = (((4') - (4)) / ((6') - (6))) * (((2') - (2)) / ((3') - (3)))
2. Apply iterative sensor S_CROP for new input window.
3. If old combined scales applied to new crop produce an impossible user window,
adjust scales to produce nearest possible window.
width_u_out = ((5') - (5)) / scale_comb
if (width_u_out > max)
scale_comb = ((5') - (5)) / max;
else if (width_u_out < min)
scale_comb = ((5') - (5)) / min;
4. Issue G_CROP to retrieve actual input window.
5. Using actual input window and calculated combined scales calculate sensor
target output window.
width_s_out = ((3') - (3)) = ((2') - (2)) / scale_comb
6. Apply iterative S_FMT for new sensor target output window.
7. Issue G_FMT to retrieve the actual sensor output window.
8. Calculate sensor scales.
scale_s = ((3') - (3)) / ((2') - (2))
9. Calculate sensor output subwindow to be cropped on CEU by applying sensor
scales to the requested window.
width_ceu = ((5') - (5)) / scale_s
10. Use CEU cropping for above calculated window.
11. Calculate CEU scales from sensor scales from results of (10) and user window
from (3)
scale_ceu = calc_scale(((5') - (5)), &width_u_out)
12. Apply CEU scales.
--
Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
|
