forked from kolesa-team/go-webp
/
options.go
92 lines (77 loc) · 2.75 KB
/
options.go
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// The MIT License (MIT)
//
// Copyright (c) 2019 Amangeldy Kadyl
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
package decoder
/*
#cgo LDFLAGS: -lwebp -lm -lpthread
#include <webp/decode.h>
*/
import "C"
import (
"errors"
"image"
)
// Options specifies webp decoding parameters
type Options struct {
Crop image.Rectangle
Scale image.Rectangle
DitheringStrength int
AlphaDitheringStrength int
BypassFiltering bool
NoFancyUpsampling bool
UseThreads bool
Flip bool
}
// GetConfig build WebPDecoderConfig for libwebp
func (o *Options) GetConfig() (*C.WebPDecoderConfig, error) {
config := C.WebPDecoderConfig{}
if C.WebPInitDecoderConfig(&config) == 0 {
return nil, errors.New("cannot init decoder config")
}
if o.BypassFiltering {
config.options.bypass_filtering = 1
}
if o.NoFancyUpsampling {
config.options.no_fancy_upsampling = 1
}
// проверяем надо ли кропнуть
if o.Crop.Max.X > 0 && o.Crop.Max.Y > 0 {
config.options.use_cropping = 1
config.options.crop_left = C.int(o.Crop.Min.X)
config.options.crop_top = C.int(o.Crop.Min.Y)
config.options.crop_width = C.int(o.Crop.Max.X)
config.options.crop_height = C.int(o.Crop.Max.Y)
}
// проверяем надо ли заскейлить
if o.Scale.Max.X > 0 && o.Scale.Max.Y > 0 {
config.options.use_scaling = 1
config.options.scaled_width = C.int(o.Scale.Max.X)
config.options.scaled_height = C.int(o.Scale.Max.Y)
}
if o.UseThreads {
config.options.use_threads = 1
}
config.options.dithering_strength = C.int(o.DitheringStrength)
if o.Flip {
config.options.flip = 1
}
config.options.alpha_dithering_strength = C.int(o.AlphaDitheringStrength)
return &config, nil
}