1 | /* |
2 | * Copyright 2017 Google Inc. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | #ifndef LIB_TXT_SRC_LINE_METRICS_H_ |
18 | #define LIB_TXT_SRC_LINE_METRICS_H_ |
19 | |
20 | #include <map> |
21 | #include <vector> |
22 | |
23 | #include "run_metrics.h" |
24 | |
25 | namespace txt { |
26 | |
27 | class LineMetrics { |
28 | public: |
29 | // The following fields are used in the layout process itself. |
30 | |
31 | // The indexes in the text buffer the line begins and ends. |
32 | size_t start_index = 0; |
33 | size_t end_index = 0; |
34 | size_t end_excluding_whitespace = 0; |
35 | size_t end_including_newline = 0; |
36 | bool hard_break = false; |
37 | |
38 | // The following fields are tracked after or during layout to provide to |
39 | // the user as well as for computing bounding boxes. |
40 | |
41 | // The final computed ascent and descent for the line. This can be impacted by |
42 | // the strut, height, scaling, as well as outlying runs that are very tall. |
43 | // |
44 | // The top edge is `baseline - ascent` and the bottom edge is `baseline + |
45 | // descent`. Ascent and descent are provided as positive numbers. Raw numbers |
46 | // for specific runs of text can be obtained in run_metrics_map. These values |
47 | // are the cumulative metrics for the entire line. |
48 | double ascent = 0.0; |
49 | double descent = 0.0; |
50 | double unscaled_ascent = 0.0; |
51 | // Total height of the paragraph including the current line. |
52 | // |
53 | // The height of the current line is `round(ascent + descent)`. |
54 | double height = 0.0; |
55 | // Width of the line. |
56 | double width = 0.0; |
57 | // The left edge of the line. The right edge can be obtained with `left + |
58 | // width` |
59 | double left = 0.0; |
60 | // The y position of the baseline for this line from the top of the paragraph. |
61 | double baseline = 0.0; |
62 | // Zero indexed line number. |
63 | size_t line_number = 0; |
64 | |
65 | // Mapping between text index ranges and the FontMetrics associated with |
66 | // them. The first run will be keyed under start_index. The metrics here |
67 | // are before layout and are the base values we calculate from. |
68 | std::map<size_t, RunMetrics> run_metrics; |
69 | |
70 | LineMetrics(); |
71 | |
72 | LineMetrics(size_t start, |
73 | size_t end, |
74 | size_t end_excluding_whitespace, |
75 | size_t end_including_newline, |
76 | bool hard_break) |
77 | : start_index(start), |
78 | end_index(end), |
79 | end_excluding_whitespace(end_excluding_whitespace), |
80 | end_including_newline(end_including_newline), |
81 | hard_break(hard_break) {} |
82 | }; |
83 | |
84 | } // namespace txt |
85 | |
86 | #endif // LIB_TXT_SRC_LINE_METRICS_H_ |
87 | |