From d744182d6c6bf57525dd04418689302bae524cb4 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Mon, 15 Jan 2018 19:19:32 -0700
Subject: [PATCH] Fix animated thumbnailer
* Use a swap image for resizing the frame (otherwise the frame gets corrupted)
* Use a linear resample filter (better output quality)
* Redraw the frame using a different technique
* Set the bounds of the image on the image config prior to re-encoding (otherwise the image has a bunch of whitespace)
This finishes #28
---
.../services/thumbnail_service/thumbnailer.go | 31 ++++++++++++++-----
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/src/github.com/turt2live/matrix-media-repo/services/thumbnail_service/thumbnailer.go b/src/github.com/turt2live/matrix-media-repo/services/thumbnail_service/thumbnailer.go
index a9cabb48..deaf66a8 100644
--- a/src/github.com/turt2live/matrix-media-repo/services/thumbnail_service/thumbnailer.go
+++ b/src/github.com/turt2live/matrix-media-repo/services/thumbnail_service/thumbnailer.go
@@ -4,8 +4,8 @@ import (
"bytes"
"context"
"errors"
- "fmt"
"image"
+ "image/color/palette"
"image/draw"
"image/gif"
"os"
@@ -96,18 +96,32 @@ func (t *thumbnailer) GenerateThumbnail(media *types.Media, width int, height in
return nil, err
}
+ // Prepare a blank frame to use as swap space
+ frameImg := image.NewRGBA(g.Image[0].Bounds())
+
for i := range g.Image {
- frameThumb, err := thumbnailFrame(g.Image[i], method, width, height, imaging.Lanczos)
+ img := g.Image[i]
+
+ // Copy the frame to a new image and use that
+ draw.Draw(frameImg, img.Bounds(), img, image.ZP, draw.Over)
+
+ // Do the thumbnailing on the copied frame
+ frameThumb, err := thumbnailFrame(frameImg, method, width, height, imaging.Linear)
if err != nil {
t.log.Error("Error generating animated thumbnail frame: " + err.Error())
return nil, err
}
- t.log.Info(fmt.Sprintf("Width = %d Height = %d FW=%d FH=%d", width, height, frameThumb.Bounds().Max.X, frameThumb.Bounds().Max.Y))
- g.Image[i] = image.NewPaletted(frameThumb.Bounds(), g.Image[i].Palette)
- draw.Draw(g.Image[i], frameThumb.Bounds(), frameThumb, image.Pt(0, 0), draw.Over)
+ //t.log.Info(fmt.Sprintf("Width = %d Height = %d FW=%d FH=%d", width, height, frameThumb.Bounds().Max.X, frameThumb.Bounds().Max.Y))
+ targetImg := image.NewPaletted(frameThumb.Bounds(), palette.Plan9)
+ draw.FloydSteinberg.Draw(targetImg, frameThumb.Bounds(), frameThumb, image.ZP)
+ g.Image[i] = targetImg
}
+ // Set the image size to the first frame's size
+ g.Config.Width = g.Image[0].Bounds().Max.X
+ g.Config.Height = g.Image[0].Bounds().Max.Y
+
err = gif.EncodeAll(imgData, g)
if err != nil {
t.log.Error("Error generating animated thumbnail: " + err.Error())
@@ -149,13 +163,14 @@ func (t *thumbnailer) GenerateThumbnail(media *types.Media, width int, height in
}
func thumbnailFrame(src image.Image, method string, width int, height int, filter imaging.ResampleFilter) (image.Image, error) {
+ var result image.Image
if method == "scale" {
- src = imaging.Fit(src, width, height, filter)
+ result = imaging.Fit(src, width, height, filter)
} else if method == "crop" {
- src = imaging.Fill(src, width, height, imaging.Center, filter)
+ result = imaging.Fill(src, width, height, imaging.Center, filter)
} else {
return nil, errors.New("unrecognized method: " + method)
}
- return src, nil
+ return result, nil
}
--
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