forked from davidbyttow/govips
/
resample.go
146 lines (117 loc) · 4.12 KB
/
resample.go
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package vips
// #include "resample.h"
import "C"
import (
"io/ioutil"
"runtime"
"unsafe"
)
// Kernel represents VipsKernel type
type Kernel int
// Kernel enum
const (
KernelAuto Kernel = -1
KernelNearest Kernel = C.VIPS_KERNEL_NEAREST
KernelLinear Kernel = C.VIPS_KERNEL_LINEAR
KernelCubic Kernel = C.VIPS_KERNEL_CUBIC
KernelLanczos2 Kernel = C.VIPS_KERNEL_LANCZOS2
KernelLanczos3 Kernel = C.VIPS_KERNEL_LANCZOS3
KernelMitchell Kernel = C.VIPS_KERNEL_MITCHELL
)
// Size represents VipsSize type
type Size int
const (
SizeBoth Size = C.VIPS_SIZE_BOTH
SizeUp Size = C.VIPS_SIZE_UP
SizeDown Size = C.VIPS_SIZE_DOWN
SizeForce Size = C.VIPS_SIZE_FORCE
SizeLast Size = C.VIPS_SIZE_LAST
)
// https://libvips.github.io/libvips/API/current/libvips-resample.html#vips-resize
func vipsResizeWithVScale(in *C.VipsImage, hscale, vscale float64, kernel Kernel) (*C.VipsImage, error) {
incOpCounter("resize")
var out *C.VipsImage
// libvips recommends Lanczos3 as the default kernel
if kernel == KernelAuto {
kernel = KernelLanczos3
}
if err := C.resize_image(in, &out, C.double(hscale), C.double(vscale), C.int(kernel)); err != 0 {
return nil, handleImageError(out)
}
return out, nil
}
func vipsThumbnail(in *C.VipsImage, width, height int, crop Interesting, size Size) (*C.VipsImage, error) {
incOpCounter("thumbnail")
var out *C.VipsImage
if err := C.thumbnail_image(in, &out, C.int(width), C.int(height), C.int(crop), C.int(size)); err != 0 {
return nil, handleImageError(out)
}
return out, nil
}
// https://www.libvips.org/API/current/libvips-resample.html#vips-thumbnail
func vipsThumbnailFromFile(filename string, width, height int, crop Interesting, size Size, params *ImportParams) (*C.VipsImage, ImageType, error) {
var out *C.VipsImage
filenameOption := filename
if params != nil {
filenameOption += "[" + params.OptionString() + "]"
}
cFileName := C.CString(filenameOption)
defer freeCString(cFileName)
if err := C.thumbnail(cFileName, &out, C.int(width), C.int(height), C.int(crop), C.int(size)); err != 0 {
err := handleImageError(out)
if src, err2 := ioutil.ReadFile(filename); err2 == nil {
if isBMP(src) {
if src2, err3 := bmpToPNG(src); err3 == nil {
return vipsThumbnailFromBuffer(src2, width, height, crop, size, params)
}
}
}
return nil, ImageTypeUnknown, err
}
imageType := vipsDetermineImageTypeFromMetaLoader(out)
return out, imageType, nil
}
// https://www.libvips.org/API/current/libvips-resample.html#vips-thumbnail-buffer
func vipsThumbnailFromBuffer(buf []byte, width, height int, crop Interesting, size Size, params *ImportParams) (*C.VipsImage, ImageType, error) {
src := buf
// Reference src here so it's not garbage collected during image initialization.
defer runtime.KeepAlive(src)
var out *C.VipsImage
var err C.int
if params == nil {
err = C.thumbnail_buffer(unsafe.Pointer(&src[0]), C.size_t(len(src)), &out, C.int(width), C.int(height), C.int(crop), C.int(size))
} else {
cOptionString := C.CString(params.OptionString())
defer freeCString(cOptionString)
err = C.thumbnail_buffer_with_option(unsafe.Pointer(&src[0]), C.size_t(len(src)), &out, C.int(width), C.int(height), C.int(crop), C.int(size), cOptionString)
}
if err != 0 {
err := handleImageError(out)
if isBMP(src) {
if src2, err2 := bmpToPNG(src); err2 == nil {
return vipsThumbnailFromBuffer(src2, width, height, crop, size, params)
}
}
return nil, ImageTypeUnknown, err
}
imageType := vipsDetermineImageTypeFromMetaLoader(out)
return out, imageType, nil
}
// https://libvips.github.io/libvips/API/current/libvips-resample.html#vips-mapim
func vipsMapim(in *C.VipsImage, index *C.VipsImage) (*C.VipsImage, error) {
incOpCounter("mapim")
var out *C.VipsImage
if err := C.mapim(in, &out, index); err != 0 {
return nil, handleImageError(out)
}
return out, nil
}
// https://libvips.github.io/libvips/API/current/libvips-histogram.html#vips-maplut
func vipsMaplut(in *C.VipsImage, lut *C.VipsImage) (*C.VipsImage, error) {
incOpCounter("maplut")
var out *C.VipsImage
if err := C.maplut(in, &out, lut); err != 0 {
return nil, handleImageError(out)
}
return out, nil
}