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@@ -0,0 +1,498 @@
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+// Copyright 2013 Beego Authors
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+//
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+// Licensed under the Apache License, Version 2.0 (the "License"): you may
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+// not use this file except in compliance with the License. You may obtain
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+// a copy of the License at
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+//
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+// http://www.apache.org/licenses/LICENSE-2.0
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+//
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+// Unless required by applicable law or agreed to in writing, software
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+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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+// License for the specific language governing permissions and limitations
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+// under the License.
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+
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+package captcha
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+
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+import (
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+ "bytes"
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+ "image"
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+ "image/color"
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+ "image/png"
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+ "io"
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+ "math"
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+)
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+
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+const (
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+ fontWidth = 11
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+ fontHeight = 18
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+ blackChar = 1
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+
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+ // Standard width and height of a captcha image.
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+ stdWidth = 240
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+ stdHeight = 80
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+
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+ // Maximum absolute skew factor of a single digit.
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+ maxSkew = 0.7
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+ // Number of background circles.
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+ circleCount = 20
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+)
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+
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+var font = [][]byte{
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+ { // 0
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ },
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+ { // 1
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ },
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+ { // 2
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+ 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ },
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+ { // 3
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+ 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0,
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+ },
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+ { // 4
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ },
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+ { // 5
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0,
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+ },
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+ { // 6
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+ 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0,
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+ 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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+ 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0,
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+ 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0,
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+ 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ },
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+ { // 7
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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+ 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0,
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+ 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0,
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+ 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0,
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+ 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0,
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+ },
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+ { // 8
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0,
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+ 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0,
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+ 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ },
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+ { // 9
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+ 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
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+ 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1,
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+ 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1,
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+ 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0,
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+ 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0,
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+ 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
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+ },
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+}
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+
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+type Image struct {
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+ *image.Paletted
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+ numWidth int
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+ numHeight int
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+ dotSize int
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+}
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+
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+var prng = &siprng{}
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+
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+// randIntn returns a pseudorandom non-negative int in range [0, n).
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+func randIntn(n int) int {
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+ return prng.Intn(n)
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+}
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+
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+// randInt returns a pseudorandom int in range [from, to].
|
|
|
|
+func randInt(from, to int) int {
|
|
|
|
+ return prng.Intn(to+1-from) + from
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+// randFloat returns a pseudorandom float64 in range [from, to].
|
|
|
|
+func randFloat(from, to float64) float64 {
|
|
|
|
+ return (to-from)*prng.Float64() + from
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func randomPalette() color.Palette {
|
|
|
|
+ p := make([]color.Color, circleCount+1)
|
|
|
|
+ // Transparent color.
|
|
|
|
+ p[0] = color.RGBA{0xFF, 0xFF, 0xFF, 0x00}
|
|
|
|
+ // Primary color.
|
|
|
|
+ prim := color.RGBA{
|
|
|
|
+ uint8(randIntn(129)),
|
|
|
|
+ uint8(randIntn(129)),
|
|
|
|
+ uint8(randIntn(129)),
|
|
|
|
+ 0xFF,
|
|
|
|
+ }
|
|
|
|
+ p[1] = prim
|
|
|
|
+ // Circle colors.
|
|
|
|
+ for i := 2; i <= circleCount; i++ {
|
|
|
|
+ p[i] = randomBrightness(prim, 255)
|
|
|
|
+ }
|
|
|
|
+ return p
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+// NewImage returns a new captcha image of the given width and height with the
|
|
|
|
+// given digits, where each digit must be in range 0-9.
|
|
|
|
+func NewImage(digits []byte, width, height int) *Image {
|
|
|
|
+ m := new(Image)
|
|
|
|
+ m.Paletted = image.NewPaletted(image.Rect(0, 0, width, height), randomPalette())
|
|
|
|
+ m.calculateSizes(width, height, len(digits))
|
|
|
|
+ // Randomly position captcha inside the image.
|
|
|
|
+ maxx := width - (m.numWidth+m.dotSize)*len(digits) - m.dotSize
|
|
|
|
+ maxy := height - m.numHeight - m.dotSize*2
|
|
|
|
+ var border int
|
|
|
|
+ if width > height {
|
|
|
|
+ border = height / 5
|
|
|
|
+ } else {
|
|
|
|
+ border = width / 5
|
|
|
|
+ }
|
|
|
|
+ x := randInt(border, maxx-border)
|
|
|
|
+ y := randInt(border, maxy-border)
|
|
|
|
+ // Draw digits.
|
|
|
|
+ for _, n := range digits {
|
|
|
|
+ m.drawDigit(font[n], x, y)
|
|
|
|
+ x += m.numWidth + m.dotSize
|
|
|
|
+ }
|
|
|
|
+ // Draw strike-through line.
|
|
|
|
+ m.strikeThrough()
|
|
|
|
+ // Apply wave distortion.
|
|
|
|
+ m.distort(randFloat(5, 10), randFloat(100, 200))
|
|
|
|
+ // Fill image with random circles.
|
|
|
|
+ m.fillWithCircles(circleCount, m.dotSize)
|
|
|
|
+ return m
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+// encodedPNG encodes an image to PNG and returns
|
|
|
|
+// the result as a byte slice.
|
|
|
|
+func (m *Image) encodedPNG() []byte {
|
|
|
|
+ var buf bytes.Buffer
|
|
|
|
+ if err := png.Encode(&buf, m.Paletted); err != nil {
|
|
|
|
+ panic(err.Error())
|
|
|
|
+ }
|
|
|
|
+ return buf.Bytes()
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+// WriteTo writes captcha image in PNG format into the given writer.
|
|
|
|
+func (m *Image) WriteTo(w io.Writer) (int64, error) {
|
|
|
|
+ n, err := w.Write(m.encodedPNG())
|
|
|
|
+ return int64(n), err
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) calculateSizes(width, height, ncount int) {
|
|
|
|
+ // Goal: fit all digits inside the image.
|
|
|
|
+ var border int
|
|
|
|
+ if width > height {
|
|
|
|
+ border = height / 4
|
|
|
|
+ } else {
|
|
|
|
+ border = width / 4
|
|
|
|
+ }
|
|
|
|
+ // Convert everything to floats for calculations.
|
|
|
|
+ w := float64(width - border*2)
|
|
|
|
+ h := float64(height - border*2)
|
|
|
|
+ // fw takes into account 1-dot spacing between digits.
|
|
|
|
+ fw := float64(fontWidth + 1)
|
|
|
|
+ fh := float64(fontHeight)
|
|
|
|
+ nc := float64(ncount)
|
|
|
|
+ // Calculate the width of a single digit taking into account only the
|
|
|
|
+ // width of the image.
|
|
|
|
+ nw := w / nc
|
|
|
|
+ // Calculate the height of a digit from this width.
|
|
|
|
+ nh := nw * fh / fw
|
|
|
|
+ // Digit too high?
|
|
|
|
+ if nh > h {
|
|
|
|
+ // Fit digits based on height.
|
|
|
|
+ nh = h
|
|
|
|
+ nw = fw / fh * nh
|
|
|
|
+ }
|
|
|
|
+ // Calculate dot size.
|
|
|
|
+ m.dotSize = int(nh / fh)
|
|
|
|
+ // Save everything, making the actual width smaller by 1 dot to account
|
|
|
|
+ // for spacing between digits.
|
|
|
|
+ m.numWidth = int(nw) - m.dotSize
|
|
|
|
+ m.numHeight = int(nh)
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) drawHorizLine(fromX, toX, y int, colorIdx uint8) {
|
|
|
|
+ for x := fromX; x <= toX; x++ {
|
|
|
|
+ m.SetColorIndex(x, y, colorIdx)
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) drawCircle(x, y, radius int, colorIdx uint8) {
|
|
|
|
+ f := 1 - radius
|
|
|
|
+ dfx := 1
|
|
|
|
+ dfy := -2 * radius
|
|
|
|
+ xo := 0
|
|
|
|
+ yo := radius
|
|
|
|
+
|
|
|
|
+ m.SetColorIndex(x, y+radius, colorIdx)
|
|
|
|
+ m.SetColorIndex(x, y-radius, colorIdx)
|
|
|
|
+ m.drawHorizLine(x-radius, x+radius, y, colorIdx)
|
|
|
|
+
|
|
|
|
+ for xo < yo {
|
|
|
|
+ if f >= 0 {
|
|
|
|
+ yo--
|
|
|
|
+ dfy += 2
|
|
|
|
+ f += dfy
|
|
|
|
+ }
|
|
|
|
+ xo++
|
|
|
|
+ dfx += 2
|
|
|
|
+ f += dfx
|
|
|
|
+ m.drawHorizLine(x-xo, x+xo, y+yo, colorIdx)
|
|
|
|
+ m.drawHorizLine(x-xo, x+xo, y-yo, colorIdx)
|
|
|
|
+ m.drawHorizLine(x-yo, x+yo, y+xo, colorIdx)
|
|
|
|
+ m.drawHorizLine(x-yo, x+yo, y-xo, colorIdx)
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) fillWithCircles(n, maxradius int) {
|
|
|
|
+ maxx := m.Bounds().Max.X
|
|
|
|
+ maxy := m.Bounds().Max.Y
|
|
|
|
+ for i := 0; i < n; i++ {
|
|
|
|
+ colorIdx := uint8(randInt(1, circleCount-1))
|
|
|
|
+ r := randInt(1, maxradius)
|
|
|
|
+ m.drawCircle(randInt(r, maxx-r), randInt(r, maxy-r), r, colorIdx)
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) strikeThrough() {
|
|
|
|
+ maxx := m.Bounds().Max.X
|
|
|
|
+ maxy := m.Bounds().Max.Y
|
|
|
|
+ y := randInt(maxy/3, maxy-maxy/3)
|
|
|
|
+ amplitude := randFloat(5, 20)
|
|
|
|
+ period := randFloat(80, 180)
|
|
|
|
+ dx := 2.0 * math.Pi / period
|
|
|
|
+ for x := 0; x < maxx; x++ {
|
|
|
|
+ xo := amplitude * math.Cos(float64(y)*dx)
|
|
|
|
+ yo := amplitude * math.Sin(float64(x)*dx)
|
|
|
|
+ for yn := 0; yn < m.dotSize; yn++ {
|
|
|
|
+ r := randInt(0, m.dotSize)
|
|
|
|
+ m.drawCircle(x+int(xo), y+int(yo)+(yn*m.dotSize), r/2, 1)
|
|
|
|
+ }
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) drawDigit(digit []byte, x, y int) {
|
|
|
|
+ skf := randFloat(-maxSkew, maxSkew)
|
|
|
|
+ xs := float64(x)
|
|
|
|
+ r := m.dotSize / 2
|
|
|
|
+ y += randInt(-r, r)
|
|
|
|
+ for yo := 0; yo < fontHeight; yo++ {
|
|
|
|
+ for xo := 0; xo < fontWidth; xo++ {
|
|
|
|
+ if digit[yo*fontWidth+xo] != blackChar {
|
|
|
|
+ continue
|
|
|
|
+ }
|
|
|
|
+ m.drawCircle(x+xo*m.dotSize, y+yo*m.dotSize, r, 1)
|
|
|
|
+ }
|
|
|
|
+ xs += skf
|
|
|
|
+ x = int(xs)
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func (m *Image) distort(amplude float64, period float64) {
|
|
|
|
+ w := m.Bounds().Max.X
|
|
|
|
+ h := m.Bounds().Max.Y
|
|
|
|
+
|
|
|
|
+ oldm := m.Paletted
|
|
|
|
+ newm := image.NewPaletted(image.Rect(0, 0, w, h), oldm.Palette)
|
|
|
|
+
|
|
|
|
+ dx := 2.0 * math.Pi / period
|
|
|
|
+ for x := 0; x < w; x++ {
|
|
|
|
+ for y := 0; y < h; y++ {
|
|
|
|
+ xo := amplude * math.Sin(float64(y)*dx)
|
|
|
|
+ yo := amplude * math.Cos(float64(x)*dx)
|
|
|
|
+ newm.SetColorIndex(x, y, oldm.ColorIndexAt(x+int(xo), y+int(yo)))
|
|
|
|
+ }
|
|
|
|
+ }
|
|
|
|
+ m.Paletted = newm
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func randomBrightness(c color.RGBA, max uint8) color.RGBA {
|
|
|
|
+ minc := min3(c.R, c.G, c.B)
|
|
|
|
+ maxc := max3(c.R, c.G, c.B)
|
|
|
|
+ if maxc > max {
|
|
|
|
+ return c
|
|
|
|
+ }
|
|
|
|
+ n := randIntn(int(max-maxc)) - int(minc)
|
|
|
|
+ return color.RGBA{
|
|
|
|
+ uint8(int(c.R) + n),
|
|
|
|
+ uint8(int(c.G) + n),
|
|
|
|
+ uint8(int(c.B) + n),
|
|
|
|
+ uint8(c.A),
|
|
|
|
+ }
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func min3(x, y, z uint8) (m uint8) {
|
|
|
|
+ m = x
|
|
|
|
+ if y < m {
|
|
|
|
+ m = y
|
|
|
|
+ }
|
|
|
|
+ if z < m {
|
|
|
|
+ m = z
|
|
|
|
+ }
|
|
|
|
+ return
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+func max3(x, y, z uint8) (m uint8) {
|
|
|
|
+ m = x
|
|
|
|
+ if y > m {
|
|
|
|
+ m = y
|
|
|
|
+ }
|
|
|
|
+ if z > m {
|
|
|
|
+ m = z
|
|
|
|
+ }
|
|
|
|
+ return
|
|
|
|
+}
|