Android CRT Screen 电视效果

Android 2.3?对关屏进行了优化，增加了一种类似于关闭电视的效果?

Android系统默认使用的关屏效果是fade，要激活旧CRT效果，需要修改以下文件，关闭fade效果。

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frameworks/base/core/res/res/values/config.xml

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1. ???<!--?If?this?is?true,?the?screen?will?fade?off.?-->????
2. -????<bool?name="config_animateScreenLights">true</bool>????
3. +????<bool?name="config_animateScreenLights">false</bool>??

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为啥如此修改就可以激活旧CRT效果，让我们跟踪下代码，先贴上相关代码：

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frameworks\base\services\java\com\Android\server\PowerManagerService.java

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1. ?475?????????????????mAnimationSetting?=?0;????
2. ?476?????????????????if?(windowScale?>?0.5f)?{????
3. ?477?????????????????????mAnimationSetting?|=?ANIM_SETTING_OFF;????
4. ?478?????????????????}????
5. ????
6. ????
7. 2284?????????public?void?run()?{????
8. 2285?????????????if?(mAnimateScreenLights)?{????
9. 2286?????????????????synchronized?(mLocks)?{????
10. 2287?????????????????????long?now?=?SystemClock.uptimeMillis();????
11. 2288?????????????????????boolean?more?=?mScreenBrightness.stepLocked();????
12. 2289?????????????????????if?(more)?{????
13. 2290?????????????????????????mScreenOffHandler.postAtTime(this,?now+(1000/60));????
14. 2291?????????????????????}????
15. 2292?????????????????}????
16. 2293?????????????}?else?{????
17. 2294?????????????????synchronized?(mLocks)?{????
18. 2295?????????????????????//?we're?turning?off????
19. 2296?????????????????????final?boolean?animate?=?animating?&&?targetValue?==?Power.BRIGHTNESS_OFF;????
20. 2297?????????????????????if?(animate)?{????
21. 2298?????????????????????????//?It's?pretty?scary?to?hold?mLocks?for?this?long,?and?we?should????
22. 2299?????????????????????????//?redesign?this,?but?it?works?for?now.????
23. 2300?????????????????????????nativeStartSurfaceFlingerAnimation(????
24. 2301?????????????????????????????????mScreenOffReason?==?WindowManagerPolicy.OFF_BECAUSE_OF_PROX_SENSOR????
25. 2302???????????????????????????????????0?:?mAnimationSetting);????
26. 2303?????????????????????}????
27. 2304?????????????????????mScreenBrightness.jumpToTargetLocked();????
28. 2305?????????????????}????
29. 2306?????????????}????
30. 2307?????????}????
31. 2308?????}??

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frameworks/base/services/jni/com_Android_server_PowerManagerService.cpp

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1. <pre?class="cpp"?name="code">????131?static?void?Android_server_PowerManagerService_nativeStartSurfaceFlingerAnimation(JNIEnv*?env,????
2. ????132?????????jobject?obj,?jint?mode)?{????
3. ????133?????sp<ISurfaceComposer>?s(ComposerService::getComposerService());????
4. ????134?????s->turnElectronBeamOff(mode);????
5. ????135?}??

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frameworks/base/services/surfaceflinger/SurfaceFlinger.cpp

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1. 2385?status_t?SurfaceFlinger::turnElectronBeamOff(int32_t?mode)????
2. 2386?{????
3. 2387?????class?MessageTurnElectronBeamOff?:?public?MessageBase?{????
4. 2388?????????SurfaceFlinger*?flinger;????
5. 2389?????????int32_t?mode;????
6. 2390?????????status_t?result;????
7. 2391?????public:????
8. 2392?????????MessageTurnElectronBeamOff(SurfaceFlinger*?flinger,?int32_t?mode)????
9. 2393?????????????:?flinger(flinger),?mode(mode),?result(PERMISSION_DENIED)?{????
10. 2394?????????}????
11. 2395?????????status_t?getResult()?const?{????
12. 2396?????????????return?result;????
13. 2397?????????}????
14. 2398?????????virtual?bool?handler()?{????
15. 2399?????????????Mutex::Autolock?_l(flinger->mStateLock);????
16. 2400?????????????result?=?flinger->turnElectronBeamOffImplLocked(mode);????
17. 2401?????????????return?true;????
18. 2402?????????}????
19. 2403?????};????
20. 2404????
21. 2405?????sp<MessageBase>?msg?=?new?MessageTurnElectronBeamOff(this,?mode);????
22. 2406?????status_t?res?=?postMessageSync(msg);????
23. 2407?????if?(res?==?NO_ERROR)?{????
24. 2408?????????res?=?static_cast<MessageTurnElectronBeamOff*>(?msg.get()?)->getResult();????
25. 2409????
26. 2410?????????//?work-around:?when?the?power-manager?calls?us?we?activate?the????
27. 2411?????????//?animation.?eventually,?the?"on"?animation?will?be?called????
28. 2412?????????//?by?the?power-manager?itself????
29. 2413?????????mElectronBeamAnimationMode?=?mode;????
30. 2414?????}????
31. 2415?????return?res;????
32. 2416?}????
33. ????
34. ????
35. 2363?status_t?SurfaceFlinger::turnElectronBeamOffImplLocked(int32_t?mode)????
36. 2364?{????
37. 2365?????DisplayHardware&?hw(graphicPlane(0).editDisplayHardware());????
38. 2366?????if?(!hw.canDraw())?{????
39. 2367?????????//?we're?already?off????
40. 2368?????????return?NO_ERROR;????
41. 2369?????}????
42. 2370?????if?(mode?&?ISurfaceComposer::eElectronBeamAnimationOff)?{????
43. 2371?????????electronBeamOffAnimationImplLocked();????
44. 2372?????}????
45. 2373????
46. 2374?????//?always?clear?the?whole?screen?at?the?end?of?the?animation????
47. 2375?????glClearColor(0,0,0,1);????
48. 2376?????glDisable(GL_SCISSOR_TEST);????
49. 2377?????glClear(GL_COLOR_BUFFER_BIT);????
50. 2378?????glEnable(GL_SCISSOR_TEST);????
51. 2379?????hw.flip(?Region(hw.bounds())?);????
52. 2380????
53. 2381?????hw.setCanDraw(false);????
54. 2382?????return?NO_ERROR;????
55. 2383?}????
56. ????
57. 2073?status_t?SurfaceFlinger::electronBeamOffAnimationImplLocked()????
58. 2074?{????
59. 2075?????status_t?result?=?PERMISSION_DENIED;????
60. 2076????
61. 2077?????if?(!GLExtensions::getInstance().haveFramebufferObject())????
62. 2078?????????return?INVALID_OPERATION;????
63. 2079????
64. 2080?????//?get?screen?geometry????
65. 2081?????const?DisplayHardware&?hw(graphicPlane(0).displayHardware());????
66. 2082?????const?uint32_t?hw_w?=?hw.getWidth();????
67. 2083?????const?uint32_t?hw_h?=?hw.getHeight();????
68. 2084?????const?Region?screenBounds(hw.bounds());????
69. 2085????
70. 2086?????GLfloat?u,?v;????
71. 2087?????GLuint?tname;????
72. 2088?????result?=?renderScreenToTextureLocked(0,?&tname,?&u,?&v);????
73. 2089?????if?(result?!=?NO_ERROR)?{????
74. 2090?????????return?result;????
75. 2091?????}????
76. 2092????
77. 2093?????GLfloat?vtx[8];????
78. 2094?????const?GLfloat?texCoords[4][2]?=?{?{0,v},?{0,0},?{u,0},?{u,v}?};????
79. 2095?????glEnable(GL_TEXTURE_2D);????
80. 2096?????glBindTexture(GL_TEXTURE_2D,?tname);????
81. 2097?????glTexEnvx(GL_TEXTURE_ENV,?GL_TEXTURE_ENV_MODE,?GL_REPLACE);????
82. 2098?????glTexParameterx(GL_TEXTURE_2D,?GL_TEXTURE_MAG_FILTER,?GL_LINEAR);????
83. 2099?????glTexParameterx(GL_TEXTURE_2D,?GL_TEXTURE_MIN_FILTER,?GL_LINEAR);????
84. 2100?????glTexCoordPointer(2,?GL_FLOAT,?0,?texCoords);????
85. 2101?????glEnableClientState(GL_TEXTURE_COORD_ARRAY);????
86. 2102?????glVertexPointer(2,?GL_FLOAT,?0,?vtx);????
87. 2103????
88. 2104?????class?s_curve_interpolator?{????
89. 2105?????????const?float?nbFrames,?s,?v;????
90. 2106?????public:????
91. 2107?????????s_curve_interpolator(int?nbFrames,?float?s)????
92. 2108?????????:?nbFrames(1.0f?/?(nbFrames-1)),?s(s),????
93. 2109???????????v(1.0f?+?expf(-s?+?0.5f*s))?{????
94. 2110?????????}????
95. 2111?????????float?operator()(int?f)?{????
96. 2112?????????????const?float?x?=?f?*?nbFrames;????
97. 2113?????????????return?((1.0f/(1.0f?+?expf(-x*s?+?0.5f*s)))?-?0.5f)?*?v?+?0.5f;????
98. 2114?????????}????
99. 2115?????};????
100. 2116????
101. 2117?????class?v_stretch?{????
102. 2118?????????const?GLfloat?hw_w,?hw_h;????
103. 2119?????public:????
104. 2120?????????v_stretch(uint32_t?hw_w,?uint32_t?hw_h)????
105. 2121?????????:?hw_w(hw_w),?hw_h(hw_h)?{????
106. 2122?????????}????
107. 2123?????????void?operator()(GLfloat*?vtx,?float?v)?{????
108. 2124?????????????const?GLfloat?w?=?hw_w?+?(hw_w?*?v);????
109. 2125?????????????const?GLfloat?h?=?hw_h?-?(hw_h?*?v);????
110. 2126?????????????const?GLfloat?x?=?(hw_w?-?w)?*?0.5f;????
111. 2127?????????????const?GLfloat?y?=?(hw_h?-?h)?*?0.5f;????
112. 2128?????????????vtx[0]?=?x;?????????vtx[1]?=?y;????
113. 2129?????????????vtx[2]?=?x;?????????vtx[3]?=?y?+?h;????
114. 2130?????????????vtx[4]?=?x?+?w;?????vtx[5]?=?y?+?h;????
115. 2131?????????????vtx[6]?=?x?+?w;?????vtx[7]?=?y;????
116. 2132?????????}????
117. 2133?????};????
118. 2134????
119. 2135?????class?h_stretch?{????
120. 2136?????????const?GLfloat?hw_w,?hw_h;????
121. 2137?????public:????
122. 2138?????????h_stretch(uint32_t?hw_w,?uint32_t?hw_h)????
123. 2139?????????:?hw_w(hw_w),?hw_h(hw_h)?{????
124. 2140?????????}????
125. 2141?????????void?operator()(GLfloat*?vtx,?float?v)?{????
126. 2142?????????????const?GLfloat?w?=?hw_w?-?(hw_w?*?v);????
127. 2143?????????????const?GLfloat?h?=?1.0f;????
128. 2144?????????????const?GLfloat?x?=?(hw_w?-?w)?*?0.5f;????
129. 2145?????????????const?GLfloat?y?=?(hw_h?-?h)?*?0.5f;????
130. 2146?????????????vtx[0]?=?x;?????????vtx[1]?=?y;????
131. 2147?????????????vtx[2]?=?x;?????????vtx[3]?=?y?+?h;????
132. 2148?????????????vtx[4]?=?x?+?w;?????vtx[5]?=?y?+?h;????
133. 2149?????????????vtx[6]?=?x?+?w;?????vtx[7]?=?y;????
134. 2150?????????}????
135. 2151?????};????
136. 2152????
137. 2153?????//?the?full?animation?is?24?frames????
138. 2154?????const?int?nbFrames?=?12;????
139. 2155?????s_curve_interpolator?itr(nbFrames,?7.5f);????
140. 2156?????s_curve_interpolator?itg(nbFrames,?8.0f);????
141. 2157?????s_curve_interpolator?itb(nbFrames,?8.5f);????
142. 2158????
143. 2159?????v_stretch?vverts(hw_w,?hw_h);????
144. 2160?????glEnable(GL_BLEND);????
145. 2161?????glBlendFunc(GL_ONE,?GL_ONE);????
146. 2162?????for?(int?i=0?;?i<nbFrames?;?i++)?{????
147. 2163?????????float?x,?y,?w,?h;????
148. 2164?????????const?float?vr?=?itr(i);????
149. 2165?????????const?float?vg?=?itg(i);????
150. 2166?????????const?float?vb?=?itb(i);????
151. 2167????
152. 2168?????????//?clear?screen????
153. 2169?????????glColorMask(1,1,1,1);????
154. 2170?????????glClear(GL_COLOR_BUFFER_BIT);????
155. 2171?????????glEnable(GL_TEXTURE_2D);????
156. 2172????
157. 2173?????????//?draw?the?red?plane????
158. 2174?????????vverts(vtx,?vr);????
159. 2175?????????glColorMask(1,0,0,1);????
160. 2176?????????glDrawArrays(GL_TRIANGLE_FAN,?0,?4);????
161. 2177????
162. 2178?????????//?draw?the?green?plane????
163. 2179?????????vverts(vtx,?vg);????
164. 2180?????????glColorMask(0,1,0,1);????
165. 2181?????????glDrawArrays(GL_TRIANGLE_FAN,?0,?4);????
166. 2182????
167. 2183?????????//?draw?the?blue?plane????
168. 2184?????????vverts(vtx,?vb);????
169. 2185?????????glColorMask(0,0,1,1);????
170. 2186?????????glDrawArrays(GL_TRIANGLE_FAN,?0,?4);????
171. 2187????
172. 2188?????????//?draw?the?white?highlight?(we?use?the?last?vertices)????
173. 2189?????????glDisable(GL_TEXTURE_2D);????
174. 2190?????????glColorMask(1,1,1,1);????
175. 2191?????????glColor4f(vg,?vg,?vg,?1);????
176. 2192?????????glDrawArrays(GL_TRIANGLE_FAN,?0,?4);????
177. 2193?????????hw.flip(screenBounds);????
178. 2194?????}????
179. 2195????
180. 2196?????h_stretch?hverts(hw_w,?hw_h);????
181. 2197?????glDisable(GL_BLEND);????
182. 2198?????glDisable(GL_TEXTURE_2D);????
183. 2199?????glColorMask(1,1,1,1);????
184. 2200?????for?(int?i=0?;?i<nbFrames?;?i++)?{????
185. 2201?????????const?float?v?=?itg(i);????
186. 2202?????????hverts(vtx,?v);????
187. 2203?????????glClear(GL_COLOR_BUFFER_BIT);????
188. 2204?????????glColor4f(1-v,?1-v,?1-v,?1);????
189. 2205?????????glDrawArrays(GL_TRIANGLE_FAN,?0,?4);????
190. 2206?????????hw.flip(screenBounds);????
191. 2207?????}????
192. 2208????
193. 2209?????glColorMask(1,1,1,1);????
194. 2210?????glEnable(GL_SCISSOR_TEST);????
195. 2211?????glDisableClientState(GL_TEXTURE_COORD_ARRAY);????
196. 2212?????glDeleteTextures(1,?&tname);????
197. 2213?????return?NO_ERROR;????
198. 2214?}????
199. 2215??

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OK，看完代码回来，首先是PowerManagerService.java中

mAnimationSetting如果标记为ANIM_SETTING_OFF，则打开旧CRT动画。

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下面关屏动作run()中，因为我们将config_animateScreenLights置为false，因此mAnimateScreenLights为fasle

分支进入else，执行nativeStartSurfaceFlingerAnimation()函数。

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nativeStartSurfaceFlingerAnimation()函数是一个JNI调用，在com_Android_server_PowerManagerService.cpp文件中，

对应surfaceflinger的s->turnElectronBeamOff(mode)函数。

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好的，现在跳入SurfaceFlinger.cpp函数，具体调用顺序是：

turnElectronBeamOff()

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turnElectronBeamOffImplLocked()

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electronBeamOffAnimationImplLocked()

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electronBeamOffAnimationImplLocked()函数将调用openGL绘值旧CRT关屏效果，大概有24帧。

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当然，该函数有许多限制，不符合就会半途退出，你就看不到动画效果啦。