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81 lines
2.7 KiB
81 lines
2.7 KiB
2 years ago
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// Copyright 2017 Eric Zhou. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain 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,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package base64Captcha
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import "math/rand"
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//DriverDigit config for captcha-engine-digit.
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type DriverDigit struct {
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// Height png height in pixel.
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Height int
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// Width Captcha png width in pixel.
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Width int
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// DefaultLen Default number of digits in captcha solution.
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Length int
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// MaxSkew max absolute skew factor of a single digit.
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MaxSkew float64
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// DotCount Number of background circles.
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DotCount int
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}
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//NewDriverDigit creates a driver of digit
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func NewDriverDigit(height int, width int, length int, maxSkew float64, dotCount int) *DriverDigit {
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return &DriverDigit{Height: height, Width: width, Length: length, MaxSkew: maxSkew, DotCount: dotCount}
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}
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//DefaultDriverDigit is a default driver of digit
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var DefaultDriverDigit = NewDriverDigit(80, 240, 5, 0.7, 80)
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//GenerateIdQuestionAnswer creates captcha content and answer
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func (d *DriverDigit) GenerateIdQuestionAnswer() (id, q, a string) {
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id = RandomId()
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digits := randomDigits(d.Length)
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a = parseDigitsToString(digits)
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return id, a, a
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}
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//DrawCaptcha creates digit captcha item
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func (d *DriverDigit) DrawCaptcha(content string) (item Item, err error) {
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// Initialize PRNG.
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itemDigit := NewItemDigit(d.Width, d.Height, d.DotCount, d.MaxSkew)
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//parse digits to string
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digits := stringToFakeByte(content)
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itemDigit.calculateSizes(d.Width, d.Height, len(digits))
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// Randomly position captcha inside the image.
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maxx := d.Width - (itemDigit.width+itemDigit.dotSize)*len(digits) - itemDigit.dotSize
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maxy := d.Height - itemDigit.height - itemDigit.dotSize*2
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var border int
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if d.Width > d.Height {
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border = d.Height / 5
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} else {
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border = d.Width / 5
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}
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x := rand.Intn(maxx-border*2) + border
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y := rand.Intn(maxy-border*2) + border
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// Draw digits.
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for _, n := range digits {
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itemDigit.drawDigit(digitFontData[n], x, y)
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x += itemDigit.width + itemDigit.dotSize
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}
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// Draw strike-through line.
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itemDigit.strikeThrough()
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// Apply wave distortion.
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itemDigit.distort(rand.Float64()*(10-5)+5, rand.Float64()*(200-100)+100)
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// Fill image with random circles.
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itemDigit.fillWithCircles(d.DotCount, itemDigit.dotSize)
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return itemDigit, nil
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}
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