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_PARAGRAPH_BUILDER_H_ |
18 | #define LIB_TXT_SRC_PARAGRAPH_BUILDER_H_ |
19 | |
20 | #include <memory> |
21 | #include <string> |
22 | |
23 | #include "flutter/fml/macros.h" |
24 | #include "font_collection.h" |
25 | #include "paragraph.h" |
26 | #include "paragraph_style.h" |
27 | #include "placeholder_run.h" |
28 | #include "text_style.h" |
29 | |
30 | namespace txt { |
31 | |
32 | class ParagraphBuilder { |
33 | public: |
34 | static std::unique_ptr<ParagraphBuilder> CreateTxtBuilder( |
35 | const ParagraphStyle& style, |
36 | std::shared_ptr<FontCollection> font_collection); |
37 | |
38 | #if FLUTTER_ENABLE_SKSHAPER |
39 | static std::unique_ptr<ParagraphBuilder> CreateSkiaBuilder( |
40 | const ParagraphStyle& style, |
41 | std::shared_ptr<FontCollection> font_collection); |
42 | #endif |
43 | |
44 | virtual ~ParagraphBuilder() = default; |
45 | |
46 | // Push a style to the stack. The corresponding text added with AddText will |
47 | // use the top-most style. |
48 | virtual void PushStyle(const TextStyle& style) = 0; |
49 | |
50 | // Remove a style from the stack. Useful to apply different styles to chunks |
51 | // of text such as bolding. |
52 | // Example: |
53 | // builder.PushStyle(normal_style); |
54 | // builder.AddText("Hello this is normal. "); |
55 | // |
56 | // builder.PushStyle(bold_style); |
57 | // builder.AddText("And this is BOLD. "); |
58 | // |
59 | // builder.Pop(); |
60 | // builder.AddText(" Back to normal again."); |
61 | virtual void Pop() = 0; |
62 | |
63 | // Returns the last TextStyle on the stack. |
64 | virtual const TextStyle& PeekStyle() = 0; |
65 | |
66 | // Adds text to the builder. Forms the proper runs to use the upper-most style |
67 | // on the style_stack_; |
68 | virtual void AddText(const std::u16string& text) = 0; |
69 | |
70 | // Pushes the information requried to leave an open space, where Flutter may |
71 | // draw a custom placeholder into. |
72 | // |
73 | // Internally, this method adds a single object replacement character (0xFFFC) |
74 | // and emplaces a new PlaceholderRun instance to the vector of inline |
75 | // placeholders. |
76 | virtual void AddPlaceholder(PlaceholderRun& span) = 0; |
77 | |
78 | // Constructs a Paragraph object that can be used to layout and paint the text |
79 | // to a SkCanvas. |
80 | virtual std::unique_ptr<Paragraph> Build() = 0; |
81 | |
82 | protected: |
83 | ParagraphBuilder() = default; |
84 | |
85 | private: |
86 | FML_DISALLOW_COPY_AND_ASSIGN(ParagraphBuilder); |
87 | }; |
88 | |
89 | } // namespace txt |
90 | |
91 | #endif // LIB_TXT_SRC_PARAGRAPH_BUILDER_H_ |
92 | |