/
bitmap_callback.go
213 lines (170 loc) · 4.02 KB
/
bitmap_callback.go
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package libcats
import (
"bytes"
"fmt"
"image"
"image/png"
"runtime"
"time"
"github.com/nfnt/resize"
"github.com/oliamb/cutter"
)
type ImageInfo struct {
Id string
Image []byte
}
type ImageCallback interface {
ImageReceived(image []byte, id string)
ImageFailed(id string)
}
type ImageCallbackToken struct {
done chan struct{}
callback ImageCallback
}
func CreateImageCallback(callback ImageCallback, width int, height int, id string, url string) *ImageCallbackToken {
token := &ImageCallbackToken{
callback: callback,
done: make(chan struct{}),
}
go token.downloadImage(id, url, width, height)
return token
}
func (token *ImageCallbackToken) Close() {
close(token.done)
}
func timeIt(start time.Time, description string) {
elapsed := time.Since(start)
loggerFunc("%s took %s", description, elapsed)
}
func (token *ImageCallbackToken) downloadImage(id string, url string, width int, height int) {
loggerFunc("downloading %s %s %dx%d", id, url, width, height)
boe, ok := <-downloadBytes(url, token.done)
if !ok {
return
}
if boe.Error != nil {
loggerFunc("failed to download %s %s %dx%d %s", id, url, width, height, boe.Error.Error())
token.callback.ImageFailed(id)
return
}
imgBytes, ok := <-scaleImg(token.done, boe.Bytes, width, height)
if !ok {
return
}
if imgBytes.Error != nil {
loggerFunc("failed to decode image %s %s %dx%d %s", id, url, width, height, imgBytes.Error.Error())
token.callback.ImageFailed(id)
return
}
select {
case <-token.done:
return
default:
start := time.Now()
token.callback.ImageReceived(imgBytes.Bytes, id)
// token.callback.ImageFailed(id)
loggerFunc("%s took %s size %d", " <- ImageReceived", time.Since(start), len(imgBytes.Bytes))
freeMemory()
printHeap()
}
}
func freeMemory() {
defer timeIt(time.Now(), "freeMemory")
runtime.GC()
// This isn't doing anything, so don't bother
// debug.FreeOSMemory()
}
func printHeap() {
memstats := new(runtime.MemStats)
runtime.ReadMemStats(memstats)
loggerFunc("memstats: Alloc = %s Sys = %s", sizeof_fmt(memstats.Alloc), sizeof_fmt(memstats.Sys))
}
var byteSizes [8]string = [...]string{
"", "K", "M", "G", "T", "P", "E", "Z",
}
func sizeof_fmt(num uint64) string {
suffix := "b"
for _, unit := range byteSizes {
if num < 1024.0 {
return fmt.Sprintf("%d %s%s", num, unit, suffix)
}
num /= 1024.0
}
return fmt.Sprintf("%d %s%s", num, "Y", suffix)
}
func scaleImg(done chan struct{}, imgBytes []byte, width int, height int) chan bytesOrError {
resultChan := make(chan bytesOrError)
go func() {
defer close(resultChan)
start := time.Now()
orgStart := start
result := bytesOrError{
Bytes: nil,
Error: nil,
}
errorOut := func(err error) {
result.Error = err
select {
case <-done:
case resultChan <- result:
}
}
img, _, err := image.Decode(bytes.NewReader(imgBytes))
if err != nil {
errorOut(err)
return
}
select {
case <-done:
return
default:
}
decoding := time.Since(start)
start = time.Now()
uWidth := uint(width)
uHight := uint(height)
if uWidth != 0 && uHight != 0 {
// full screen images!
if uWidth > uHight {
uHight = 0
} else {
uWidth = 0
}
img = resize.Resize(uWidth, uHight, img, resize.Bilinear)
} else {
loggerFunc("invalid width and height")
}
select {
case <-done:
return
default:
}
resizing := time.Since(start)
start = time.Now()
img, err = cutter.Crop(img, cutter.Config{
Width: width,
Height: height,
Mode: cutter.Centered,
})
if err != nil {
errorOut(err)
return
}
// loggerFunc("cutting image down from %+v to %+v", orgBounds, img.Bounds())
buf := new(bytes.Buffer)
e := png.Encoder{
CompressionLevel: png.NoCompression,
}
if err := e.Encode(buf, img); err != nil {
errorOut(err)
return
}
loggerFunc("(decode/resize/encode) took %s/%s/%s total: %s", decoding, resizing, time.Since(start), time.Since(orgStart))
result.Bytes = buf.Bytes()
select {
case <-done:
case resultChan <- result:
}
}()
return resultChan
}