diff options
Diffstat (limited to 'vendor/gitea.com/go-chi/captcha/image.go')
| -rw-r--r-- | vendor/gitea.com/go-chi/captcha/image.go | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/vendor/gitea.com/go-chi/captcha/image.go b/vendor/gitea.com/go-chi/captcha/image.go new file mode 100644 index 0000000000..abe087437a --- /dev/null +++ b/vendor/gitea.com/go-chi/captcha/image.go @@ -0,0 +1,505 @@ +// Copyright 2013 Beego Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"): you may +// not use this file except in compliance with the License. You may obtain +// a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +// License for the specific language governing permissions and limitations +// under the License. + +package captcha + +import ( + "bytes" + "image" + "image/color" + "image/png" + "io" + "math" +) + +const ( + fontWidth = 11 + fontHeight = 18 + blackChar = 1 + + // Standard width and height of a captcha image. + stdWidth = 240 + stdHeight = 80 + + // Maximum absolute skew factor of a single digit. + maxSkew = 0.7 + // Number of background circles. + circleCount = 20 +) + +var font = [][]byte{ + { // 0 + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, + 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + }, + { // 1 + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + }, + { // 2 + 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + }, + { // 3 + 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, + }, + { // 4 + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, + 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, + 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, + 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + }, + { // 5 + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, + }, + { // 6 + 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, + 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, + 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, + 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, + 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, + 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, + 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + }, + { // 7 + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, + 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, + }, + { // 8 + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, + 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, + 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, + 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, + 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + }, + { // 9 + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, + 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, + 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, + 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, + 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, + }, +} + +type Image struct { + *image.Paletted + numWidth int + numHeight int + dotSize int +} + +var prng = &siprng{} + +// randIntn returns a pseudorandom non-negative int in range [0, n). +func randIntn(n int) int { + return prng.Intn(n) +} + +// 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(primary color.Palette) color.Palette { + p := make([]color.Color, circleCount+1) + // Transparent color. + p[0] = color.RGBA{0xFF, 0xFF, 0xFF, 0x00} + // Primary color. + var prim color.RGBA + if len(primary) == 0 { + prim = color.RGBA{ + uint8(randIntn(129)), + uint8(randIntn(129)), + uint8(randIntn(129)), + 0xFF, + } + } else { + r, g, b, a := primary[randIntn(len(primary)-1)].RGBA() + prim = color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)} + } + 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. The digit's color is +// chosen by random from the colorPalette. +func NewImage(digits []byte, width, height int, colorPalette color.Palette) *Image { + m := new(Image) + m.Paletted = image.NewPaletted(image.Rect(0, 0, width, height), randomPalette(colorPalette)) + 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 +} |