go-libwebp

commit 8b9f86c3cf35e5319469a98f6a6a0a707757aadd
parent 61bcd809df050051345098e0c46884ccc52c8c97
Author: Jack Mordaunt <jackmordaunt.dev@gmail.com>
Date:   Wed,  3 Jan 2024 16:31:37 +0800

lib/dynamic: add decode and fix lossy panic with cgo

Due a bug in purego, we cannot use float parameters while cgo is enabled on linux.
When cgo is enabled, we force the use of lossless encoding.

Signed-off-by: Jack Mordaunt <jackmordaunt.dev@gmail.com>

Diffstat:
A
lib/dynamic/webp/encode_cgo.go
 | 
16
++++++++++++++++
A
lib/dynamic/webp/encode_default.go
 | 
17
+++++++++++++++++
M
lib/dynamic/webp/lib.go
 | 
69
++++++++++++++++++++-------------------------------------------------
M
lib/dynamic/webp/lib_darwin_amd64.go
 | 
5
+----
M
lib/dynamic/webp/lib_linux_amd64.go
 | 
2
+-

5 files changed, 55 insertions(+), 54 deletions(-)
diff --git a/lib/dynamic/webp/encode_cgo.go b/lib/dynamic/webp/encode_cgo.go
@@ -0,0 +1,16 @@
+//go:build linux && cgo
+
+package webp
+
+import (
+	"image"
+	"io"
+
+	"git.sr.ht/~jackmordaunt/go-libwebp/lib/common"
+)
+
+// HACK: always use lossless when cgo is activated on linux. cgo on linux provokes
+// a bug in purego when using float arguments.
+func encodeImpl(w io.Writer, m *image.RGBA, quality float32) error {
+	return common.Encode(w, m, quality, wrappedLossless, WebPFree)
+}
diff --git a/lib/dynamic/webp/encode_default.go b/lib/dynamic/webp/encode_default.go
@@ -0,0 +1,17 @@
+//go:build !(linux && cgo)
+
+package webp
+
+import (
+	"image"
+	"io"
+
+	"git.sr.ht/~jackmordaunt/go-libwebp/lib/common"
+)
+
+func encodeImpl(w io.Writer, m *image.RGBA, quality float32) error {
+	if quality >= 1.0 {
+		return common.Encode(w, m, quality, wrappedLossless, WebPFree)
+	}
+	return common.Encode(w, m, quality, WebPEncodeRGBA, WebPFree)
+}
diff --git a/lib/dynamic/webp/lib.go b/lib/dynamic/webp/lib.go
@@ -2,17 +2,20 @@ package webp
 
 import (
 	"fmt"
-	"unsafe"
+	"image"
+	"io"
 
+	"git.sr.ht/~jackmordaunt/go-libwebp/lib/common"
 	"github.com/ebitengine/purego"
 )
 
 var (
 	_libwebp uintptr
 
-	_WebPEncodeLosslessRGBA func(uintptr, uintptr, uintptr, uintptr, uintptr) uintptr
-	_WebPEncodeRGBA         func(uintptr, uintptr, uintptr, uintptr, uintptr, uintptr) uintptr
-	_WebPFree               func(uintptr)
+	WebPEncodeLosslessRGBA func(in uintptr, width int32, height int32, bps int32, out uintptr) (size uint64)
+	WebPEncodeRGBA         func(in uintptr, width int32, height int32, bps int32, quality float32, out uintptr) (size uint64)
+	WebPDecodeRGBA         func(data uintptr, size uint64, width uintptr, height uintptr) uintptr
+	WebPFree               func(ptr uintptr)
 )
 
 func loadLibrary() (uintptr, error) {
@@ -33,55 +36,23 @@ func Init() (err error) {
 		return err
 	}
 
-	_WebPEncodeLosslessRGBA = func() (fn func(uintptr, uintptr, uintptr, uintptr, uintptr) uintptr) {
-		purego.RegisterLibFunc(&fn, _libwebp, "WebPEncodeLosslessRGBA")
-		return
-	}()
-
-	_WebPEncodeRGBA = func() (fn func(uintptr, uintptr, uintptr, uintptr, uintptr, uintptr) uintptr) {
-		purego.RegisterLibFunc(&fn, _libwebp, "WebPEncodeRGBA")
-		return
-	}()
-
-	_WebPFree = func() (fn func(uintptr)) {
-		purego.RegisterLibFunc(&fn, _libwebp, "WebPFree")
-		return
-	}()
+	purego.RegisterLibFunc(&WebPEncodeLosslessRGBA, _libwebp, "WebPEncodeLosslessRGBA")
+	purego.RegisterLibFunc(&WebPEncodeRGBA, _libwebp, "WebPEncodeRGBA")
+	purego.RegisterLibFunc(&WebPDecodeRGBA, _libwebp, "WebPDecodeRGBA")
+	purego.RegisterLibFunc(&WebPFree, _libwebp, "WebPFree")
 
 	return nil
 }
 
-func EncodeImpl(
-	in unsafe.Pointer,
-	w int32,
-	h int32,
-	bps int32,
-	q float32,
-	out unsafe.Pointer,
-) uint64 {
-	Init()
-	var sz uintptr
-	if q >= 1.0 {
-		sz = _WebPEncodeLosslessRGBA(
-			uintptr(in),
-			uintptr(w),
-			uintptr(h),
-			uintptr(bps),
-			uintptr(out),
-		)
-	} else {
-		sz = _WebPEncodeRGBA(
-			uintptr(in),
-			uintptr(w),
-			uintptr(h),
-			uintptr(bps),
-			uintptr(q),
-			uintptr(out),
-		)
-	}
-	return uint64(sz)
+func DecodeImpl(buf []byte) (image.Image, error) {
+	return common.Decode(buf, WebPDecodeRGBA, WebPFree)
+}
+
+func EncodeImpl(w io.Writer, m *image.RGBA, quality float32) error {
+	return encodeImpl(w, m, quality)
 }
 
-func FreeImpl(ptr unsafe.Pointer) {
-	_WebPFree(uintptr(ptr))
+// wrappedLossless drops the quality param and does a lossless encode.
+func wrappedLossless(in uintptr, w int32, h int32, bps int32, _ float32, out uintptr) uint64 {
+	return WebPEncodeLosslessRGBA(in, w, h, bps, out)
 }
diff --git a/lib/dynamic/webp/lib_darwin_amd64.go b/lib/dynamic/webp/lib_darwin_amd64.go
@@ -8,9 +8,6 @@ import (
 
 const libraryName = "libwebp.dylib"
 
-//go:embed blobs/libwebp.dylib
-var libraryData []byte
-
 func dlopen(name string) (uintptr, error) {
-	return purego.Dlopen(libraryName, purego.RTLD_NOW|purego.RTLD_GLOBAL)
+	return purego.Dlopen(libraryName, purego.RTLD_LAZY|purego.RTLD_GLOBAL)
 }
diff --git a/lib/dynamic/webp/lib_linux_amd64.go b/lib/dynamic/webp/lib_linux_amd64.go
@@ -9,5 +9,5 @@ import (
 const libraryName = "libwebp.so"
 
 func dlopen(name string) (uintptr, error) {
-	return purego.Dlopen(libraryName, purego.RTLD_NOW|purego.RTLD_GLOBAL)
+	return purego.Dlopen(libraryName, purego.RTLD_LAZY|purego.RTLD_GLOBAL)
 }