OpenShot Library | libopenshot  0.2.7
ChromaKey.cpp
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1 /**
2  * @file
3  * @brief Source file for ChromaKey class
4  * @author Jonathan Thomas <jonathan@openshot.org>
5  *
6  * @ref License
7  */
8 
9 /* LICENSE
10  *
11  * Copyright (c) 2008-2019 OpenShot Studios, LLC
12  * <http://www.openshotstudios.com/>. This file is part of
13  * OpenShot Library (libopenshot), an open-source project dedicated to
14  * delivering high quality video editing and animation solutions to the
15  * world. For more information visit <http://www.openshot.org/>.
16  *
17  * OpenShot Library (libopenshot) is free software: you can redistribute it
18  * and/or modify it under the terms of the GNU Lesser General Public License
19  * as published by the Free Software Foundation, either version 3 of the
20  * License, or (at your option) any later version.
21  *
22  * OpenShot Library (libopenshot) is distributed in the hope that it will be
23  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25  * GNU Lesser General Public License for more details.
26  *
27  * You should have received a copy of the GNU Lesser General Public License
28  * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
29  */
30 
31 #include "ChromaKey.h"
32 #include "Exceptions.h"
33 
34 using namespace openshot;
35 
36 /// Blank constructor, useful when using Json to load the effect properties
37 ChromaKey::ChromaKey() : fuzz(5.0) {
38  // Init default color
39  color = Color();
40 
41  // Init effect properties
42  init_effect_details();
43 }
44 
45 // Default constructor, which takes an openshot::Color object and a 'fuzz' factor, which
46 // is used to determine how similar colored pixels are matched. The higher the fuzz, the
47 // more colors are matched.
48 ChromaKey::ChromaKey(Color color, Keyframe fuzz) : color(color), fuzz(fuzz)
49 {
50  // Init effect properties
51  init_effect_details();
52 }
53 
54 // Init effect settings
55 void ChromaKey::init_effect_details()
56 {
57  /// Initialize the values of the EffectInfo struct.
59 
60  /// Set the effect info
61  info.class_name = "ChromaKey";
62  info.name = "Chroma Key (Greenscreen)";
63  info.description = "Replaces the color (or chroma) of the frame with transparency (i.e. keys out the color).";
64  info.has_audio = false;
65  info.has_video = true;
66 }
67 
68 // This method is required for all derived classes of EffectBase, and returns a
69 // modified openshot::Frame object
70 std::shared_ptr<openshot::Frame> ChromaKey::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
71 {
72  // Determine the current HSL (Hue, Saturation, Lightness) for the Chrome
73  int threshold = fuzz.GetInt(frame_number);
74  long mask_R = color.red.GetInt(frame_number);
75  long mask_G = color.green.GetInt(frame_number);
76  long mask_B = color.blue.GetInt(frame_number);
77 
78  // Get source image's pixels
79  std::shared_ptr<QImage> image = frame->GetImage();
80  unsigned char *pixels = (unsigned char *) image->bits();
81 
82  // Loop through pixels
83  for (int pixel = 0, byte_index=0; pixel < image->width() * image->height(); pixel++, byte_index+=4)
84  {
85  // Get the RGB values from the pixel
86  // Remove the premultiplied alpha values from R,G,B
87  float A = float(pixels[byte_index + 3]);
88  unsigned char R = (pixels[byte_index] / A) * 255.0;
89  unsigned char G = (pixels[byte_index + 1] / A) * 255.0;
90  unsigned char B = (pixels[byte_index + 2] / A) * 255.0;
91 
92  // Get distance between mask color and pixel color
93  long distance = Color::GetDistance((long)R, (long)G, (long)B, mask_R, mask_G, mask_B);
94 
95  if (distance <= threshold) {
96  // MATCHED - Make pixel transparent
97  // Due to premultiplied alpha, we must also zero out
98  // the individual color channels (or else artifacts are left behind)
99  pixels[byte_index] = 0;
100  pixels[byte_index + 1] = 0;
101  pixels[byte_index + 2] = 0;
102  pixels[byte_index + 3] = 0;
103  }
104  }
105 
106  // return the modified frame
107  return frame;
108 }
109 
110 // Generate JSON string of this object
111 std::string ChromaKey::Json() const {
112 
113  // Return formatted string
114  return JsonValue().toStyledString();
115 }
116 
117 // Generate Json::Value for this object
118 Json::Value ChromaKey::JsonValue() const {
119 
120  // Create root json object
121  Json::Value root = EffectBase::JsonValue(); // get parent properties
122  root["type"] = info.class_name;
123  root["color"] = color.JsonValue();
124  root["fuzz"] = fuzz.JsonValue();
125 
126  // return JsonValue
127  return root;
128 }
129 
130 // Load JSON string into this object
131 void ChromaKey::SetJson(const std::string value) {
132 
133  // Parse JSON string into JSON objects
134  try
135  {
136  const Json::Value root = openshot::stringToJson(value);
137  // Set all values that match
138  SetJsonValue(root);
139  }
140  catch (const std::exception& e)
141  {
142  // Error parsing JSON (or missing keys)
143  throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
144  }
145 }
146 
147 // Load Json::Value into this object
148 void ChromaKey::SetJsonValue(const Json::Value root) {
149 
150  // Set parent data
152 
153  // Set data from Json (if key is found)
154  if (!root["color"].isNull())
155  color.SetJsonValue(root["color"]);
156  if (!root["fuzz"].isNull())
157  fuzz.SetJsonValue(root["fuzz"]);
158 }
159 
160 // Get all properties for a specific frame
161 std::string ChromaKey::PropertiesJSON(int64_t requested_frame) const {
162 
163  // Generate JSON properties list
164  Json::Value root;
165  root["id"] = add_property_json("ID", 0.0, "string", Id(), NULL, -1, -1, true, requested_frame);
166  root["position"] = add_property_json("Position", Position(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
167  root["layer"] = add_property_json("Track", Layer(), "int", "", NULL, 0, 20, false, requested_frame);
168  root["start"] = add_property_json("Start", Start(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
169  root["end"] = add_property_json("End", End(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
170  root["duration"] = add_property_json("Duration", Duration(), "float", "", NULL, 0, 30 * 60 * 60 * 48, true, requested_frame);
171 
172  // Keyframes
173  root["color"] = add_property_json("Key Color", 0.0, "color", "", &color.red, 0, 255, false, requested_frame);
174  root["color"]["red"] = add_property_json("Red", color.red.GetValue(requested_frame), "float", "", &color.red, 0, 255, false, requested_frame);
175  root["color"]["blue"] = add_property_json("Blue", color.blue.GetValue(requested_frame), "float", "", &color.blue, 0, 255, false, requested_frame);
176  root["color"]["green"] = add_property_json("Green", color.green.GetValue(requested_frame), "float", "", &color.green, 0, 255, false, requested_frame);
177  root["fuzz"] = add_property_json("Fuzz", fuzz.GetValue(requested_frame), "float", "", &fuzz, 0, 125, false, requested_frame);
178 
179  // Set the parent effect which properties this effect will inherit
180  root["parent_effect_id"] = add_property_json("Parent", 0.0, "string", info.parent_effect_id, NULL, -1, -1, false, requested_frame);
181 
182  // Return formatted string
183  return root.toStyledString();
184 }
Header file for ChromaKey class.
Header file for all Exception classes.
void SetJson(const std::string value) override
Load JSON string into this object.
Definition: ChromaKey.cpp:131
ChromaKey()
Blank constructor, useful when using Json to load the effect properties.
Definition: ChromaKey.cpp:37
std::string Json() const override
Generate JSON string of this object.
Definition: ChromaKey.cpp:111
std::string PropertiesJSON(int64_t requested_frame) const override
Definition: ChromaKey.cpp:161
std::shared_ptr< openshot::Frame > GetFrame(int64_t frame_number) override
This method is required for all derived classes of ClipBase, and returns a new openshot::Frame object...
Definition: ChromaKey.h:81
Json::Value JsonValue() const override
Generate Json::Value for this object.
Definition: ChromaKey.cpp:118
void SetJsonValue(const Json::Value root) override
Load Json::Value into this object.
Definition: ChromaKey.cpp:148
float End() const
Get end position (in seconds) of clip (trim end of video)
Definition: ClipBase.h:111
float Start() const
Get start position (in seconds) of clip (trim start of video)
Definition: ClipBase.h:110
float Duration() const
Get the length of this clip (in seconds)
Definition: ClipBase.h:112
std::string Id() const
Get the Id of this clip object.
Definition: ClipBase.h:107
int Layer() const
Get layer of clip on timeline (lower number is covered by higher numbers)
Definition: ClipBase.h:109
float Position() const
Get position on timeline (in seconds)
Definition: ClipBase.h:108
Json::Value add_property_json(std::string name, float value, std::string type, std::string memo, const Keyframe *keyframe, float min_value, float max_value, bool readonly, int64_t requested_frame) const
Generate JSON for a property.
Definition: ClipBase.cpp:68
This class represents a color (used on the timeline and clips)
Definition: Color.h:45
openshot::Keyframe blue
Curve representing the red value (0 - 255)
Definition: Color.h:50
openshot::Keyframe red
Curve representing the red value (0 - 255)
Definition: Color.h:48
openshot::Keyframe green
Curve representing the green value (0 - 255)
Definition: Color.h:49
void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
Definition: Color.cpp:138
static long GetDistance(long R1, long G1, long B1, long R2, long G2, long B2)
Get the distance between 2 RGB pairs. (0=identical colors, 10=very close colors, 760=very different c...
Definition: Color.cpp:90
Json::Value JsonValue() const
Generate Json::Value for this object.
Definition: Color.cpp:107
virtual Json::Value JsonValue() const
Generate Json::Value for this object.
Definition: EffectBase.cpp:92
virtual void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
Definition: EffectBase.cpp:127
EffectInfoStruct info
Information about the current effect.
Definition: EffectBase.h:87
Exception for invalid JSON.
Definition: Exceptions.h:206
A Keyframe is a collection of Point instances, which is used to vary a number or property over time.
Definition: KeyFrame.h:72
int GetInt(int64_t index) const
Get the rounded INT value at a specific index.
Definition: KeyFrame.cpp:292
void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
Definition: KeyFrame.cpp:368
double GetValue(int64_t index) const
Get the value at a specific index.
Definition: KeyFrame.cpp:268
Json::Value JsonValue() const
Generate Json::Value for this object.
Definition: KeyFrame.cpp:335
This namespace is the default namespace for all code in the openshot library.
Definition: Compressor.h:47
const Json::Value stringToJson(const std::string value)
Definition: Json.cpp:34
bool has_video
Determines if this effect manipulates the image of a frame.
Definition: EffectBase.h:58
std::string parent_effect_id
Id of the parent effect (if there is one)
Definition: EffectBase.h:57
bool has_audio
Determines if this effect manipulates the audio of a frame.
Definition: EffectBase.h:59
std::string class_name
The class name of the effect.
Definition: EffectBase.h:54
std::string name
The name of the effect.
Definition: EffectBase.h:55
std::string description
The description of this effect and what it does.
Definition: EffectBase.h:56