1 /*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "include/private/SkTo.h"
9 #include "src/core/SkAnalyticEdge.h"
10 #include "src/core/SkFDot6.h"
11 #include "src/core/SkMathPriv.h"
12 #include <utility>
13
14 static const int kInverseTableSize = 1024; // SK_FDot6One * 16
15
quick_inverse(SkFDot6 x)16 static inline SkFixed quick_inverse(SkFDot6 x) {
17 SkASSERT(SkAbs32(x) < kInverseTableSize);
18 static const int32_t table[kInverseTableSize * 2] = {
19 -4096, -4100, -4104, -4108, -4112, -4116, -4120, -4124, -4128, -4132, -4136,
20 -4140, -4144, -4148, -4152, -4156, -4161, -4165, -4169, -4173, -4177, -4181,
21 -4185, -4190, -4194, -4198, -4202, -4206, -4211, -4215, -4219, -4223, -4228,
22 -4232, -4236, -4240, -4245, -4249, -4253, -4258, -4262, -4266, -4271, -4275,
23 -4279, -4284, -4288, -4293, -4297, -4301, -4306, -4310, -4315, -4319, -4324,
24 -4328, -4332, -4337, -4341, -4346, -4350, -4355, -4359, -4364, -4369, -4373,
25 -4378, -4382, -4387, -4391, -4396, -4401, -4405, -4410, -4415, -4419, -4424,
26 -4429, -4433, -4438, -4443, -4447, -4452, -4457, -4462, -4466, -4471, -4476,
27 -4481, -4485, -4490, -4495, -4500, -4505, -4510, -4514, -4519, -4524, -4529,
28 -4534, -4539, -4544, -4549, -4554, -4559, -4563, -4568, -4573, -4578, -4583,
29 -4588, -4593, -4599, -4604, -4609, -4614, -4619, -4624, -4629, -4634, -4639,
30 -4644, -4650, -4655, -4660, -4665, -4670, -4675, -4681, -4686, -4691, -4696,
31 -4702, -4707, -4712, -4718, -4723, -4728, -4733, -4739, -4744, -4750, -4755,
32 -4760, -4766, -4771, -4777, -4782, -4788, -4793, -4798, -4804, -4809, -4815,
33 -4821, -4826, -4832, -4837, -4843, -4848, -4854, -4860, -4865, -4871, -4877,
34 -4882, -4888, -4894, -4899, -4905, -4911, -4917, -4922, -4928, -4934, -4940,
35 -4946, -4951, -4957, -4963, -4969, -4975, -4981, -4987, -4993, -4999, -5005,
36 -5011, -5017, -5023, -5029, -5035, -5041, -5047, -5053, -5059, -5065, -5071,
37 -5077, -5084, -5090, -5096, -5102, -5108, -5115, -5121, -5127, -5133, -5140,
38 -5146, -5152, -5159, -5165, -5171, -5178, -5184, -5190, -5197, -5203, -5210,
39 -5216, -5223, -5229, -5236, -5242, -5249, -5256, -5262, -5269, -5275, -5282,
40 -5289, -5295, -5302, -5309, -5315, -5322, -5329, -5336, -5343, -5349, -5356,
41 -5363, -5370, -5377, -5384, -5391, -5398, -5405, -5412, -5418, -5426, -5433,
42 -5440, -5447, -5454, -5461, -5468, -5475, -5482, -5489, -5497, -5504, -5511,
43 -5518, -5526, -5533, -5540, -5548, -5555, -5562, -5570, -5577, -5584, -5592,
44 -5599, -5607, -5614, -5622, -5629, -5637, -5645, -5652, -5660, -5667, -5675,
45 -5683, -5691, -5698, -5706, -5714, -5722, -5729, -5737, -5745, -5753, -5761,
46 -5769, -5777, -5785, -5793, -5801, -5809, -5817, -5825, -5833, -5841, -5849,
47 -5857, -5866, -5874, -5882, -5890, -5899, -5907, -5915, -5924, -5932, -5940,
48 -5949, -5957, -5966, -5974, -5983, -5991, -6000, -6009, -6017, -6026, -6034,
49 -6043, -6052, -6061, -6069, -6078, -6087, -6096, -6105, -6114, -6123, -6132,
50 -6141, -6150, -6159, -6168, -6177, -6186, -6195, -6204, -6213, -6223, -6232,
51 -6241, -6250, -6260, -6269, -6278, -6288, -6297, -6307, -6316, -6326, -6335,
52 -6345, -6355, -6364, -6374, -6384, -6393, -6403, -6413, -6423, -6432, -6442,
53 -6452, -6462, -6472, -6482, -6492, -6502, -6512, -6523, -6533, -6543, -6553,
54 -6563, -6574, -6584, -6594, -6605, -6615, -6626, -6636, -6647, -6657, -6668,
55 -6678, -6689, -6700, -6710, -6721, -6732, -6743, -6754, -6765, -6775, -6786,
56 -6797, -6808, -6820, -6831, -6842, -6853, -6864, -6875, -6887, -6898, -6909,
57 -6921, -6932, -6944, -6955, -6967, -6978, -6990, -7002, -7013, -7025, -7037,
58 -7049, -7061, -7073, -7084, -7096, -7108, -7121, -7133, -7145, -7157, -7169,
59 -7182, -7194, -7206, -7219, -7231, -7244, -7256, -7269, -7281, -7294, -7307,
60 -7319, -7332, -7345, -7358, -7371, -7384, -7397, -7410, -7423, -7436, -7449,
61 -7463, -7476, -7489, -7503, -7516, -7530, -7543, -7557, -7570, -7584, -7598,
62 -7612, -7626, -7639, -7653, -7667, -7681, -7695, -7710, -7724, -7738, -7752,
63 -7767, -7781, -7796, -7810, -7825, -7839, -7854, -7869, -7884, -7898, -7913,
64 -7928, -7943, -7958, -7973, -7989, -8004, -8019, -8035, -8050, -8065, -8081,
65 -8097, -8112, -8128, -8144, -8160, -8176, -8192, -8208, -8224, -8240, -8256,
66 -8272, -8289, -8305, -8322, -8338, -8355, -8371, -8388, -8405, -8422, -8439,
67 -8456, -8473, -8490, -8507, -8525, -8542, -8559, -8577, -8594, -8612, -8630,
68 -8648, -8665, -8683, -8701, -8719, -8738, -8756, -8774, -8793, -8811, -8830,
69 -8848, -8867, -8886, -8905, -8924, -8943, -8962, -8981, -9000, -9020, -9039,
70 -9058, -9078, -9098, -9118, -9137, -9157, -9177, -9198, -9218, -9238, -9258,
71 -9279, -9300, -9320, -9341, -9362, -9383, -9404, -9425, -9446, -9467, -9489,
72 -9510, -9532, -9554, -9576, -9597, -9619, -9642, -9664, -9686, -9709, -9731,
73 -9754, -9776, -9799, -9822, -9845, -9868, -9892, -9915, -9939, -9962, -9986,
74 -10010, -10034, -10058, -10082, -10106, -10131, -10155, -10180, -10205, -10230,
75 -10255, -10280, -10305, -10330, -10356, -10381, -10407, -10433, -10459, -10485,
76 -10512, -10538, -10564, -10591, -10618, -10645, -10672, -10699, -10727, -10754,
77 -10782, -10810, -10837, -10866, -10894, -10922, -10951, -10979, -11008, -11037,
78 -11066, -11096, -11125, -11155, -11184, -11214, -11244, -11275, -11305, -11335,
79 -11366, -11397, -11428, -11459, -11491, -11522, -11554, -11586, -11618, -11650,
80 -11683, -11715, -11748, -11781, -11814, -11848, -11881, -11915, -11949, -11983,
81 -12018, -12052, -12087, -12122, -12157, -12192, -12228, -12264, -12300, -12336,
82 -12372, -12409, -12446, -12483, -12520, -12557, -12595, -12633, -12671, -12710,
83 -12748, -12787, -12826, -12865, -12905, -12945, -12985, -13025, -13066, -13107,
84 -13148, -13189, -13231, -13273, -13315, -13357, -13400, -13443, -13486, -13530,
85 -13573, -13617, -13662, -13706, -13751, -13797, -13842, -13888, -13934, -13981,
86 -14027, -14074, -14122, -14169, -14217, -14266, -14315, -14364, -14413, -14463,
87 -14513, -14563, -14614, -14665, -14716, -14768, -14820, -14873, -14926, -14979,
88 -15033, -15087, -15141, -15196, -15252, -15307, -15363, -15420, -15477, -15534,
89 -15592, -15650, -15709, -15768, -15827, -15887, -15947, -16008, -16070, -16131,
90 -16194, -16256, -16320, -16384, -16448, -16513, -16578, -16644, -16710, -16777,
91 -16844, -16912, -16980, -17050, -17119, -17189, -17260, -17331, -17403, -17476,
92 -17549, -17623, -17697, -17772, -17848, -17924, -18001, -18078, -18157, -18236,
93 -18315, -18396, -18477, -18558, -18641, -18724, -18808, -18893, -18978, -19065,
94 -19152, -19239, -19328, -19418, -19508, -19599, -19691, -19784, -19878, -19972,
95 -20068, -20164, -20262, -20360, -20460, -20560, -20661, -20763, -20867, -20971,
96 -21076, -21183, -21290, -21399, -21509, -21620, -21732, -21845, -21959, -22075,
97 -22192, -22310, -22429, -22550, -22671, -22795, -22919, -23045, -23172, -23301,
98 -23431, -23563, -23696, -23831, -23967, -24105, -24244, -24385, -24528, -24672,
99 -24818, -24966, -25115, -25266, -25420, -25575, -25731, -25890, -26051, -26214,
100 -26379, -26546, -26715, -26886, -27060, -27235, -27413, -27594, -27776, -27962,
101 -28149, -28339, -28532, -28728, -28926, -29127, -29330, -29537, -29746, -29959,
102 -30174, -30393, -30615, -30840, -31068, -31300, -31536, -31775, -32017, -32263,
103 -32513, -32768, -33026, -33288, -33554, -33825, -34100, -34379, -34663, -34952,
104 -35246, -35544, -35848, -36157, -36472, -36792, -37117, -37449, -37786, -38130,
105 -38479, -38836, -39199, -39568, -39945, -40329, -40721, -41120, -41527, -41943,
106 -42366, -42799, -43240, -43690, -44150, -44620, -45100, -45590, -46091, -46603,
107 -47127, -47662, -48210, -48770, -49344, -49932, -50533, -51150, -51781, -52428,
108 -53092, -53773, -54471, -55188, -55924, -56679, -57456, -58254, -59074, -59918,
109 -60787, -61680, -62601, -63550, -64527, -65536, -66576, -67650, -68759, -69905,
110 -71089, -72315, -73584, -74898, -76260, -77672, -79137, -80659, -82241, -83886,
111 -85598, -87381, -89240, -91180, -93206, -95325, -97541, -99864, -102300,
112 -104857, -107546, -110376, -113359, -116508, -119837, -123361, -127100, -131072,
113 -135300, -139810, -144631, -149796, -155344, -161319, -167772, -174762, -182361,
114 -190650, -199728, -209715, -220752, -233016, -246723, -262144, -279620, -299593,
115 -322638, -349525, -381300, -419430, -466033, -524288, -599186, -699050, -838860,
116 -1048576, -1398101, -2097152, -4194304, 0, 4194304, 2097152, 1398101, 1048576,
117 838860, 699050, 599186, 524288, 466033, 419430, 381300, 349525, 322638, 299593,
118 279620, 262144, 246723, 233016, 220752, 209715, 199728, 190650, 182361, 174762,
119 167772, 161319, 155344, 149796, 144631, 139810, 135300, 131072, 127100, 123361,
120 119837, 116508, 113359, 110376, 107546, 104857, 102300, 99864, 97541, 95325,
121 93206, 91180, 89240, 87381, 85598, 83886, 82241, 80659, 79137, 77672, 76260,
122 74898, 73584, 72315, 71089, 69905, 68759, 67650, 66576, 65536, 64527, 63550,
123 62601, 61680, 60787, 59918, 59074, 58254, 57456, 56679, 55924, 55188, 54471,
124 53773, 53092, 52428, 51781, 51150, 50533, 49932, 49344, 48770, 48210, 47662,
125 47127, 46603, 46091, 45590, 45100, 44620, 44150, 43690, 43240, 42799, 42366,
126 41943, 41527, 41120, 40721, 40329, 39945, 39568, 39199, 38836, 38479, 38130,
127 37786, 37449, 37117, 36792, 36472, 36157, 35848, 35544, 35246, 34952, 34663,
128 34379, 34100, 33825, 33554, 33288, 33026, 32768, 32513, 32263, 32017, 31775,
129 31536, 31300, 31068, 30840, 30615, 30393, 30174, 29959, 29746, 29537, 29330,
130 29127, 28926, 28728, 28532, 28339, 28149, 27962, 27776, 27594, 27413, 27235,
131 27060, 26886, 26715, 26546, 26379, 26214, 26051, 25890, 25731, 25575, 25420,
132 25266, 25115, 24966, 24818, 24672, 24528, 24385, 24244, 24105, 23967, 23831,
133 23696, 23563, 23431, 23301, 23172, 23045, 22919, 22795, 22671, 22550, 22429,
134 22310, 22192, 22075, 21959, 21845, 21732, 21620, 21509, 21399, 21290, 21183,
135 21076, 20971, 20867, 20763, 20661, 20560, 20460, 20360, 20262, 20164, 20068,
136 19972, 19878, 19784, 19691, 19599, 19508, 19418, 19328, 19239, 19152, 19065,
137 18978, 18893, 18808, 18724, 18641, 18558, 18477, 18396, 18315, 18236, 18157,
138 18078, 18001, 17924, 17848, 17772, 17697, 17623, 17549, 17476, 17403, 17331,
139 17260, 17189, 17119, 17050, 16980, 16912, 16844, 16777, 16710, 16644, 16578,
140 16513, 16448, 16384, 16320, 16256, 16194, 16131, 16070, 16008, 15947, 15887,
141 15827, 15768, 15709, 15650, 15592, 15534, 15477, 15420, 15363, 15307, 15252,
142 15196, 15141, 15087, 15033, 14979, 14926, 14873, 14820, 14768, 14716, 14665,
143 14614, 14563, 14513, 14463, 14413, 14364, 14315, 14266, 14217, 14169, 14122,
144 14074, 14027, 13981, 13934, 13888, 13842, 13797, 13751, 13706, 13662, 13617,
145 13573, 13530, 13486, 13443, 13400, 13357, 13315, 13273, 13231, 13189, 13148,
146 13107, 13066, 13025, 12985, 12945, 12905, 12865, 12826, 12787, 12748, 12710,
147 12671, 12633, 12595, 12557, 12520, 12483, 12446, 12409, 12372, 12336, 12300,
148 12264, 12228, 12192, 12157, 12122, 12087, 12052, 12018, 11983, 11949, 11915,
149 11881, 11848, 11814, 11781, 11748, 11715, 11683, 11650, 11618, 11586, 11554,
150 11522, 11491, 11459, 11428, 11397, 11366, 11335, 11305, 11275, 11244, 11214,
151 11184, 11155, 11125, 11096, 11066, 11037, 11008, 10979, 10951, 10922, 10894,
152 10866, 10837, 10810, 10782, 10754, 10727, 10699, 10672, 10645, 10618, 10591,
153 10564, 10538, 10512, 10485, 10459, 10433, 10407, 10381, 10356, 10330, 10305,
154 10280, 10255, 10230, 10205, 10180, 10155, 10131, 10106, 10082, 10058, 10034,
155 10010, 9986, 9962, 9939, 9915, 9892, 9868, 9845, 9822, 9799, 9776, 9754, 9731,
156 9709, 9686, 9664, 9642, 9619, 9597, 9576, 9554, 9532, 9510, 9489, 9467, 9446,
157 9425, 9404, 9383, 9362, 9341, 9320, 9300, 9279, 9258, 9238, 9218, 9198, 9177,
158 9157, 9137, 9118, 9098, 9078, 9058, 9039, 9020, 9000, 8981, 8962, 8943, 8924,
159 8905, 8886, 8867, 8848, 8830, 8811, 8793, 8774, 8756, 8738, 8719, 8701, 8683,
160 8665, 8648, 8630, 8612, 8594, 8577, 8559, 8542, 8525, 8507, 8490, 8473, 8456,
161 8439, 8422, 8405, 8388, 8371, 8355, 8338, 8322, 8305, 8289, 8272, 8256, 8240,
162 8224, 8208, 8192, 8176, 8160, 8144, 8128, 8112, 8097, 8081, 8065, 8050, 8035,
163 8019, 8004, 7989, 7973, 7958, 7943, 7928, 7913, 7898, 7884, 7869, 7854, 7839,
164 7825, 7810, 7796, 7781, 7767, 7752, 7738, 7724, 7710, 7695, 7681, 7667, 7653,
165 7639, 7626, 7612, 7598, 7584, 7570, 7557, 7543, 7530, 7516, 7503, 7489, 7476,
166 7463, 7449, 7436, 7423, 7410, 7397, 7384, 7371, 7358, 7345, 7332, 7319, 7307,
167 7294, 7281, 7269, 7256, 7244, 7231, 7219, 7206, 7194, 7182, 7169, 7157, 7145,
168 7133, 7121, 7108, 7096, 7084, 7073, 7061, 7049, 7037, 7025, 7013, 7002, 6990,
169 6978, 6967, 6955, 6944, 6932, 6921, 6909, 6898, 6887, 6875, 6864, 6853, 6842,
170 6831, 6820, 6808, 6797, 6786, 6775, 6765, 6754, 6743, 6732, 6721, 6710, 6700,
171 6689, 6678, 6668, 6657, 6647, 6636, 6626, 6615, 6605, 6594, 6584, 6574, 6563,
172 6553, 6543, 6533, 6523, 6512, 6502, 6492, 6482, 6472, 6462, 6452, 6442, 6432,
173 6423, 6413, 6403, 6393, 6384, 6374, 6364, 6355, 6345, 6335, 6326, 6316, 6307,
174 6297, 6288, 6278, 6269, 6260, 6250, 6241, 6232, 6223, 6213, 6204, 6195, 6186,
175 6177, 6168, 6159, 6150, 6141, 6132, 6123, 6114, 6105, 6096, 6087, 6078, 6069,
176 6061, 6052, 6043, 6034, 6026, 6017, 6009, 6000, 5991, 5983, 5974, 5966, 5957,
177 5949, 5940, 5932, 5924, 5915, 5907, 5899, 5890, 5882, 5874, 5866, 5857, 5849,
178 5841, 5833, 5825, 5817, 5809, 5801, 5793, 5785, 5777, 5769, 5761, 5753, 5745,
179 5737, 5729, 5722, 5714, 5706, 5698, 5691, 5683, 5675, 5667, 5660, 5652, 5645,
180 5637, 5629, 5622, 5614, 5607, 5599, 5592, 5584, 5577, 5570, 5562, 5555, 5548,
181 5540, 5533, 5526, 5518, 5511, 5504, 5497, 5489, 5482, 5475, 5468, 5461, 5454,
182 5447, 5440, 5433, 5426, 5418, 5412, 5405, 5398, 5391, 5384, 5377, 5370, 5363,
183 5356, 5349, 5343, 5336, 5329, 5322, 5315, 5309, 5302, 5295, 5289, 5282, 5275,
184 5269, 5262, 5256, 5249, 5242, 5236, 5229, 5223, 5216, 5210, 5203, 5197, 5190,
185 5184, 5178, 5171, 5165, 5159, 5152, 5146, 5140, 5133, 5127, 5121, 5115, 5108,
186 5102, 5096, 5090, 5084, 5077, 5071, 5065, 5059, 5053, 5047, 5041, 5035, 5029,
187 5023, 5017, 5011, 5005, 4999, 4993, 4987, 4981, 4975, 4969, 4963, 4957, 4951,
188 4946, 4940, 4934, 4928, 4922, 4917, 4911, 4905, 4899, 4894, 4888, 4882, 4877,
189 4871, 4865, 4860, 4854, 4848, 4843, 4837, 4832, 4826, 4821, 4815, 4809, 4804,
190 4798, 4793, 4788, 4782, 4777, 4771, 4766, 4760, 4755, 4750, 4744, 4739, 4733,
191 4728, 4723, 4718, 4712, 4707, 4702, 4696, 4691, 4686, 4681, 4675, 4670, 4665,
192 4660, 4655, 4650, 4644, 4639, 4634, 4629, 4624, 4619, 4614, 4609, 4604, 4599,
193 4593, 4588, 4583, 4578, 4573, 4568, 4563, 4559, 4554, 4549, 4544, 4539, 4534,
194 4529, 4524, 4519, 4514, 4510, 4505, 4500, 4495, 4490, 4485, 4481, 4476, 4471,
195 4466, 4462, 4457, 4452, 4447, 4443, 4438, 4433, 4429, 4424, 4419, 4415, 4410,
196 4405, 4401, 4396, 4391, 4387, 4382, 4378, 4373, 4369, 4364, 4359, 4355, 4350,
197 4346, 4341, 4337, 4332, 4328, 4324, 4319, 4315, 4310, 4306, 4301, 4297, 4293,
198 4288, 4284, 4279, 4275, 4271, 4266, 4262, 4258, 4253, 4249, 4245, 4240, 4236,
199 4232, 4228, 4223, 4219, 4215, 4211, 4206, 4202, 4198, 4194, 4190, 4185, 4181,
200 4177, 4173, 4169, 4165, 4161, 4156, 4152, 4148, 4144, 4140, 4136, 4132, 4128,
201 4124, 4120, 4116, 4112, 4108, 4104, 4100
202 };
203 return table[kInverseTableSize + x];
204 }
205
quick_div(SkFDot6 a,SkFDot6 b)206 static inline SkFixed quick_div(SkFDot6 a, SkFDot6 b) {
207 const int kMinBits = 3; // abs(b) should be at least (1 << kMinBits) for quick division
208 const int kMaxBits = 31; // Number of bits available in signed int
209 // Given abs(b) <= (1 << kMinBits), the inverse of abs(b) is at most 1 << (22 - kMinBits) in
210 // SkFixed format. Hence abs(a) should be less than kMaxAbsA
211 const int kMaxAbsA = 1 << (kMaxBits - (22 - kMinBits));
212 SkFDot6 abs_a = SkAbs32(a);
213 SkFDot6 abs_b = SkAbs32(b);
214 if (abs_b >= (1 << kMinBits) && abs_b < kInverseTableSize && abs_a < kMaxAbsA) {
215 SkASSERT((int64_t)a * quick_inverse(b) <= SK_MaxS32
216 && (int64_t)a * quick_inverse(b) >= SK_MinS32);
217 SkFixed ourAnswer = (a * quick_inverse(b)) >> 6;
218 SkASSERT(
219 (SkFDot6Div(a,b) == 0 && ourAnswer == 0) ||
220 SkFixedDiv(SkAbs32(SkFDot6Div(a,b) - ourAnswer), SkAbs32(SkFDot6Div(a,b))) <= 1 << 10
221 );
222 return ourAnswer;
223 }
224 return SkFDot6Div(a, b);
225 }
226
setLine(const SkPoint & p0,const SkPoint & p1)227 bool SkAnalyticEdge::setLine(const SkPoint& p0, const SkPoint& p1) {
228 fRiteE = nullptr;
229
230 // We must set X/Y using the same way (e.g., times 4, to FDot6, then to Fixed) as Quads/Cubics.
231 // Otherwise the order of the edge might be wrong due to precision limit.
232 const int accuracy = kDefaultAccuracy;
233 #ifdef SK_RASTERIZE_EVEN_ROUNDING
234 SkFixed x0 = SkFDot6ToFixed(SkScalarRoundToFDot6(p0.fX, accuracy)) >> accuracy;
235 SkFixed y0 = SnapY(SkFDot6ToFixed(SkScalarRoundToFDot6(p0.fY, accuracy)) >> accuracy);
236 SkFixed x1 = SkFDot6ToFixed(SkScalarRoundToFDot6(p1.fX, accuracy)) >> accuracy;
237 SkFixed y1 = SnapY(SkFDot6ToFixed(SkScalarRoundToFDot6(p1.fY, accuracy)) >> accuracy);
238 #else
239 const int multiplier = (1 << kDefaultAccuracy);
240 SkFixed x0 = SkFDot6ToFixed(SkScalarToFDot6(p0.fX * multiplier)) >> accuracy;
241 SkFixed y0 = SnapY(SkFDot6ToFixed(SkScalarToFDot6(p0.fY * multiplier)) >> accuracy);
242 SkFixed x1 = SkFDot6ToFixed(SkScalarToFDot6(p1.fX * multiplier)) >> accuracy;
243 SkFixed y1 = SnapY(SkFDot6ToFixed(SkScalarToFDot6(p1.fY * multiplier)) >> accuracy);
244 #endif
245
246 int winding = 1;
247
248 if (y0 > y1) {
249 using std::swap;
250 swap(x0, x1);
251 swap(y0, y1);
252 winding = -1;
253 }
254
255 // are we a zero-height line?
256 SkFDot6 dy = SkFixedToFDot6(y1 - y0);
257 if (dy == 0) {
258 return false;
259 }
260 SkFDot6 dx = SkFixedToFDot6(x1 - x0);
261 SkFixed slope = quick_div(dx, dy);
262 SkFixed absSlope = SkAbs32(slope);
263
264 fX = x0;
265 fDX = slope;
266 fUpperX = x0;
267 fY = y0;
268 fUpperY = y0;
269 fLowerY = y1;
270 fDY = dx == 0 || slope == 0 ? SK_MaxS32 : absSlope < kInverseTableSize
271 ? quick_inverse(absSlope)
272 : SkAbs32(quick_div(dy, dx));
273 fCurveCount = 0;
274 fWinding = SkToS8(winding);
275 fCurveShift = 0;
276
277 return true;
278 }
279
280 // This will become a bottleneck for small ovals rendering if we call SkFixedDiv twice here.
281 // Therefore, we'll let the outter function compute the slope once and send in the value.
282 // Moreover, we'll compute fDY by quickly lookup the inverse table (if possible).
updateLine(SkFixed x0,SkFixed y0,SkFixed x1,SkFixed y1,SkFixed slope)283 bool SkAnalyticEdge::updateLine(SkFixed x0, SkFixed y0, SkFixed x1, SkFixed y1, SkFixed slope) {
284 // Since we send in the slope, we can no longer snap y inside this function.
285 // If we don't send in the slope, or we do some more sophisticated snapping, this function
286 // could be a performance bottleneck.
287 SkASSERT(fWinding == 1 || fWinding == -1);
288 SkASSERT(fCurveCount != 0);
289
290 // We don't chop at y extrema for cubics so the y is not guaranteed to be increasing for them.
291 // In that case, we have to swap x/y and negate the winding.
292 if (y0 > y1) {
293 using std::swap;
294 swap(x0, x1);
295 swap(y0, y1);
296 fWinding = -fWinding;
297 }
298
299 SkASSERT(y0 <= y1);
300
301 SkFDot6 dx = SkFixedToFDot6(x1 - x0);
302 SkFDot6 dy = SkFixedToFDot6(y1 - y0);
303
304 // are we a zero-height line?
305 if (dy == 0) {
306 return false;
307 }
308
309 SkASSERT(slope < SK_MaxS32);
310
311 SkFDot6 absSlope = SkAbs32(SkFixedToFDot6(slope));
312 fX = x0;
313 fDX = slope;
314 fUpperX = x0;
315 fY = y0;
316 fUpperY = y0;
317 fLowerY = y1;
318 fDY = (dx == 0 || slope == 0)
319 ? SK_MaxS32
320 : absSlope < kInverseTableSize
321 ? quick_inverse(absSlope)
322 : SkAbs32(quick_div(dy, dx));
323
324 return true;
325 }
326
update(SkFixed last_y,bool sortY)327 bool SkAnalyticEdge::update(SkFixed last_y, bool sortY) {
328 SkASSERT(last_y >= fLowerY); // we shouldn't update edge if last_y < fLowerY
329 if (fCurveCount < 0) {
330 return static_cast<SkAnalyticCubicEdge*>(this)->updateCubic(sortY);
331 } else if (fCurveCount > 0) {
332 return static_cast<SkAnalyticQuadraticEdge*>(this)->updateQuadratic();
333 }
334 return false;
335 }
336
setQuadratic(const SkPoint pts[3])337 bool SkAnalyticQuadraticEdge::setQuadratic(const SkPoint pts[3]) {
338 fRiteE = nullptr;
339
340 if (!fQEdge.setQuadraticWithoutUpdate(pts, kDefaultAccuracy)) {
341 return false;
342 }
343 fQEdge.fQx >>= kDefaultAccuracy;
344 fQEdge.fQy >>= kDefaultAccuracy;
345 fQEdge.fQDx >>= kDefaultAccuracy;
346 fQEdge.fQDy >>= kDefaultAccuracy;
347 fQEdge.fQDDx >>= kDefaultAccuracy;
348 fQEdge.fQDDy >>= kDefaultAccuracy;
349 fQEdge.fQLastX >>= kDefaultAccuracy;
350 fQEdge.fQLastY >>= kDefaultAccuracy;
351 fQEdge.fQy = SnapY(fQEdge.fQy);
352 fQEdge.fQLastY = SnapY(fQEdge.fQLastY);
353
354 fWinding = fQEdge.fWinding;
355 fCurveCount = fQEdge.fCurveCount;
356 fCurveShift = fQEdge.fCurveShift;
357
358 fSnappedX = fQEdge.fQx;
359 fSnappedY = fQEdge.fQy;
360
361 return this->updateQuadratic();
362 }
363
updateQuadratic()364 bool SkAnalyticQuadraticEdge::updateQuadratic() {
365 int success = 0; // initialize to fail!
366 int count = fCurveCount;
367 SkFixed oldx = fQEdge.fQx;
368 SkFixed oldy = fQEdge.fQy;
369 SkFixed dx = fQEdge.fQDx;
370 SkFixed dy = fQEdge.fQDy;
371 SkFixed newx, newy, newSnappedX, newSnappedY;
372 int shift = fCurveShift;
373
374 SkASSERT(count > 0);
375
376 do {
377 SkFixed slope;
378 if (--count > 0)
379 {
380 newx = oldx + (dx >> shift);
381 newy = oldy + (dy >> shift);
382 if (SkAbs32(dy >> shift) >= SK_Fixed1 * 2) { // only snap when dy is large enough
383 SkFDot6 diffY = SkFixedToFDot6(newy - fSnappedY);
384 slope = diffY ? quick_div(SkFixedToFDot6(newx - fSnappedX), diffY)
385 : SK_MaxS32;
386 newSnappedY = SkTMin<SkFixed>(fQEdge.fQLastY, SkFixedRoundToFixed(newy));
387 newSnappedX = newx - SkFixedMul(slope, newy - newSnappedY);
388 } else {
389 newSnappedY = SkTMin(fQEdge.fQLastY, SnapY(newy));
390 newSnappedX = newx;
391 SkFDot6 diffY = SkFixedToFDot6(newSnappedY - fSnappedY);
392 slope = diffY ? quick_div(SkFixedToFDot6(newx - fSnappedX), diffY)
393 : SK_MaxS32;
394 }
395 dx += fQEdge.fQDDx;
396 dy += fQEdge.fQDDy;
397 }
398 else // last segment
399 {
400 newx = fQEdge.fQLastX;
401 newy = fQEdge.fQLastY;
402 newSnappedY = newy;
403 newSnappedX = newx;
404 SkFDot6 diffY = (newy - fSnappedY) >> 10;
405 slope = diffY ? quick_div((newx - fSnappedX) >> 10, diffY) : SK_MaxS32;
406 }
407 if (slope < SK_MaxS32) {
408 success = this->updateLine(fSnappedX, fSnappedY, newSnappedX, newSnappedY, slope);
409 }
410 oldx = newx;
411 oldy = newy;
412 } while (count > 0 && !success);
413
414 SkASSERT(newSnappedY <= fQEdge.fQLastY);
415
416 fQEdge.fQx = newx;
417 fQEdge.fQy = newy;
418 fQEdge.fQDx = dx;
419 fQEdge.fQDy = dy;
420 fSnappedX = newSnappedX;
421 fSnappedY = newSnappedY;
422 fCurveCount = SkToS8(count);
423 return success;
424 }
425
setCubic(const SkPoint pts[4],bool sortY)426 bool SkAnalyticCubicEdge::setCubic(const SkPoint pts[4], bool sortY) {
427 fRiteE = nullptr;
428
429 if (!fCEdge.setCubicWithoutUpdate(pts, kDefaultAccuracy, sortY)) {
430 return false;
431 }
432
433 fCEdge.fCx >>= kDefaultAccuracy;
434 fCEdge.fCy >>= kDefaultAccuracy;
435 fCEdge.fCDx >>= kDefaultAccuracy;
436 fCEdge.fCDy >>= kDefaultAccuracy;
437 fCEdge.fCDDx >>= kDefaultAccuracy;
438 fCEdge.fCDDy >>= kDefaultAccuracy;
439 fCEdge.fCDDDx >>= kDefaultAccuracy;
440 fCEdge.fCDDDy >>= kDefaultAccuracy;
441 fCEdge.fCLastX >>= kDefaultAccuracy;
442 fCEdge.fCLastY >>= kDefaultAccuracy;
443 fCEdge.fCy = SnapY(fCEdge.fCy);
444 fCEdge.fCLastY = SnapY(fCEdge.fCLastY);
445
446 fWinding = fCEdge.fWinding;
447 fCurveCount = fCEdge.fCurveCount;
448 fCurveShift = fCEdge.fCurveShift;
449 fCubicDShift = fCEdge.fCubicDShift;
450
451 fSnappedY = fCEdge.fCy;
452
453 return this->updateCubic(sortY);
454 }
455
updateCubic(bool sortY)456 bool SkAnalyticCubicEdge::updateCubic(bool sortY) {
457 int success;
458 int count = fCurveCount;
459 SkFixed oldx = fCEdge.fCx;
460 SkFixed oldy = fCEdge.fCy;
461 SkFixed newx, newy;
462 const int ddshift = fCurveShift;
463 const int dshift = fCubicDShift;
464
465 SkASSERT(count < 0);
466
467 do {
468 if (++count < 0) {
469 newx = oldx + (fCEdge.fCDx >> dshift);
470 fCEdge.fCDx += fCEdge.fCDDx >> ddshift;
471 fCEdge.fCDDx += fCEdge.fCDDDx;
472
473 newy = oldy + (fCEdge.fCDy >> dshift);
474 fCEdge.fCDy += fCEdge.fCDDy >> ddshift;
475 fCEdge.fCDDy += fCEdge.fCDDDy;
476 }
477 else { // last segment
478 newx = fCEdge.fCLastX;
479 newy = fCEdge.fCLastY;
480 }
481
482 // we want to say SkASSERT(oldy <= newy), but our finite fixedpoint
483 // doesn't always achieve that, so we have to explicitly pin it here.
484 if (sortY && newy < oldy) {
485 newy = oldy;
486 }
487
488 SkFixed newSnappedY = SnapY(newy);
489 // we want to SkASSERT(snappedNewY <= fCEdge.fCLastY), but our finite fixedpoint
490 // doesn't always achieve that, so we have to explicitly pin it here.
491 if (sortY && fCEdge.fCLastY < newSnappedY) {
492 newSnappedY = fCEdge.fCLastY;
493 count = 0;
494 }
495
496 SkFixed slope = SkFixedToFDot6(newSnappedY - fSnappedY) == 0
497 ? SK_MaxS32
498 : SkFDot6Div(SkFixedToFDot6(newx - oldx),
499 SkFixedToFDot6(newSnappedY - fSnappedY));
500
501 success = this->updateLine(oldx, fSnappedY, newx, newSnappedY, slope);
502
503 oldx = newx;
504 oldy = newy;
505 fSnappedY = newSnappedY;
506 } while (count < 0 && !success);
507
508 fCEdge.fCx = newx;
509 fCEdge.fCy = newy;
510 fCurveCount = SkToS8(count);
511 return success;
512 }
513