mirror of
https://github.com/willnorris/imageproxy.git
synced 2025-01-27 23:04:32 -05:00
87 lines
2.2 KiB
Go
87 lines
2.2 KiB
Go
|
// Copyright 2013 Daniel Pupius. All rights reserved.
|
||
|
|
//
|
||
|
|
// 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 main
|
||
|
|
|
||
|
|
// This demonstrates a solution to resizing animated gifs.
|
||
|
|
//
|
||
|
|
// Frames in an animated gif aren't necessarily the same size, subsequent
|
||
|
|
// frames are overlayed on previous frames. Therefore, resizing the frames
|
||
|
|
// individually may cause problems due to aliasing of transparent pixels. This
|
||
|
|
// example tries to avoid this by building frames from all previous frames and
|
||
|
|
// resizing the frames as RGB.
|
||
|
|
|
||
|
|
import (
|
||
|
|
"image"
|
||
|
|
"image/color/palette"
|
||
|
|
"image/draw"
|
||
|
|
"image/gif"
|
||
|
|
"log"
|
||
|
|
"os"
|
||
|
|
|
||
|
|
"github.com/nfnt/resize"
|
||
|
|
)
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
process("shapes")
|
||
|
|
process("blob")
|
||
|
|
}
|
||
|
|
|
||
|
|
func process(filename string) {
|
||
|
|
|
||
|
|
// Open image file.
|
||
|
|
f, err := os.Open(filename + ".gif")
|
||
|
|
if err != nil {
|
||
|
|
log.Fatal(err.Error())
|
||
|
|
}
|
||
|
|
defer f.Close()
|
||
|
|
|
||
|
|
// Decode the original gif.
|
||
|
|
im, err := gif.DecodeAll(f)
|
||
|
|
if err != nil {
|
||
|
|
log.Fatal(err.Error())
|
||
|
|
}
|
||
|
|
|
||
|
|
// Create a new RGBA image to hold the incremental frames.
|
||
|
|
firstFrame := im.Image[0].Bounds()
|
||
|
|
b := image.Rect(0, 0, firstFrame.Dx(), firstFrame.Dy())
|
||
|
|
img := image.NewRGBA(b)
|
||
|
|
|
||
|
|
// Resize each frame.
|
||
|
|
for index, frame := range im.Image {
|
||
|
|
bounds := frame.Bounds()
|
||
|
|
draw.Draw(img, bounds, frame, bounds.Min, draw.Over)
|
||
|
|
im.Image[index] = ImageToPaletted(ProcessImage(img))
|
||
|
|
}
|
||
|
|
|
||
|
|
// Write resized gif.
|
||
|
|
out, err := os.Create(filename + ".out.fixed.gif")
|
||
|
|
if err != nil {
|
||
|
|
log.Fatal(err.Error())
|
||
|
|
}
|
||
|
|
defer out.Close()
|
||
|
|
gif.EncodeAll(out, im)
|
||
|
|
}
|
||
|
|
|
||
|
|
func ProcessImage(img image.Image) image.Image {
|
||
|
|
return resize.Resize(250, 0, img, resize.NearestNeighbor)
|
||
|
|
}
|
||
|
|
|
||
|
|
func ImageToPaletted(img image.Image) *image.Paletted {
|
||
|
|
b := img.Bounds()
|
||
|
|
pm := image.NewPaletted(b, palette.Plan9)
|
||
|
|
draw.FloydSteinberg.Draw(pm, b, img, image.ZP)
|
||
|
|
return pm
|
||
|
|
}
|