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mirror of https://github.com/imgproxy/imgproxy.git synced 2025-01-08 10:45:04 +02:00
imgproxy/processing/scale_on_load.go
2021-11-01 19:45:45 +06:00

73 lines
1.6 KiB
Go

package processing
import (
"math"
"github.com/imgproxy/imgproxy/v3/config"
"github.com/imgproxy/imgproxy/v3/imagedata"
"github.com/imgproxy/imgproxy/v3/imagetype"
"github.com/imgproxy/imgproxy/v3/imath"
"github.com/imgproxy/imgproxy/v3/options"
"github.com/imgproxy/imgproxy/v3/vips"
)
func canScaleOnLoad(imgtype imagetype.Type, scale float64) bool {
if imgtype == imagetype.SVG {
return true
}
if config.DisableShrinkOnLoad || scale >= 1 {
return false
}
return imgtype == imagetype.JPEG || imgtype == imagetype.WEBP
}
func calcJpegShink(scale float64, imgtype imagetype.Type) int {
shrink := int(1.0 / scale)
switch {
case shrink >= 8:
return 8
case shrink >= 4:
return 4
case shrink >= 2:
return 2
}
return 1
}
func scaleOnLoad(pctx *pipelineContext, img *vips.Image, po *options.ProcessingOptions, imgdata *imagedata.ImageData) error {
prescale := math.Max(pctx.wscale, pctx.hscale)
if pctx.trimmed || prescale == 1 || imgdata == nil || !canScaleOnLoad(pctx.imgtype, prescale) {
return nil
}
jpegShrink := calcJpegShink(prescale, pctx.imgtype)
if pctx.imgtype == imagetype.JPEG && jpegShrink == 1 {
return nil
}
if err := img.Load(imgdata, jpegShrink, prescale, 1); err != nil {
return err
}
// Update scales after scale-on-load
newWidth, newHeight, _, _ := extractMeta(img, po.Rotate, po.AutoRotate)
pctx.wscale = float64(pctx.srcWidth) * pctx.wscale / float64(newWidth)
if newWidth == imath.Scale(newWidth, pctx.wscale) {
pctx.wscale = 1.0
}
pctx.hscale = float64(pctx.srcHeight) * pctx.hscale / float64(newHeight)
if newHeight == imath.Scale(newHeight, pctx.hscale) {
pctx.hscale = 1.0
}
return nil
}