LibGfx/WebP: Move some code shared by loader and writer to WebPShared.h

Has (no-op) the effect of adding a few missing default-initializers for
the copy in WebPLoader.cpp.

No behavior change.

Userland/Libraries/LibGfx/ImageFormats/WebPLoader.cpp

@@ -13,6 +13,7 @@
 #include <LibGfx/ImageFormats/WebPLoader.h>
 #include <LibGfx/ImageFormats/WebPLoaderLossless.h>
 #include <LibGfx/ImageFormats/WebPLoaderLossy.h>
+#include <LibGfx/ImageFormats/WebPShared.h>
 #include <LibGfx/Painter.h>
 #include <LibRIFF/ChunkID.h>
 #include <LibRIFF/RIFF.h>
@@ -24,43 +25,6 @@ namespace Gfx {
 
 namespace {
 
-struct VP8XHeader {
-    bool has_icc;
-    bool has_alpha;
-    bool has_exif;
-    bool has_xmp;
-    bool has_animation;
-    u32 width;
-    u32 height;
-};
-
-struct ANIMChunk {
-    u32 background_color;
-    u16 loop_count;
-};
-
-struct ANMFChunk {
-    u32 frame_x;
-    u32 frame_y;
-    u32 frame_width;
-    u32 frame_height;
-    u32 frame_duration_in_milliseconds;
-
-    enum class BlendingMethod {
-        UseAlphaBlending = 0,
-        DoNotBlend = 1,
-    };
-    BlendingMethod blending_method;
-
-    enum class DisposalMethod {
-        DoNotDispose = 0,
-        DisposeToBackgroundColor = 1,
-    };
-    DisposalMethod disposal_method;
-
-    ReadonlyBytes frame_data;
-};
-
 // "For a still image, the image data consists of a single frame, which is made up of:
 //     An optional alpha subchunk.
 //     A bitstream subchunk."

Userland/Libraries/LibGfx/ImageFormats/WebPShared.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2024, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Span.h>
+#include <AK/Types.h>
+
+namespace Gfx {
+
+struct VP8XHeader {
+    bool has_icc { false };
+    bool has_alpha { false };
+    bool has_exif { false };
+    bool has_xmp { false };
+    bool has_animation { false };
+    u32 width { 0 };
+    u32 height { 0 };
+};
+
+struct ANIMChunk {
+    u32 background_color { 0 };
+    u16 loop_count { 0 };
+};
+
+struct ANMFChunk {
+    u32 frame_x { 0 };
+    u32 frame_y { 0 };
+    u32 frame_width { 0 };
+    u32 frame_height { 0 };
+    u32 frame_duration_in_milliseconds { 0 };
+
+    enum class BlendingMethod {
+        UseAlphaBlending = 0,
+        DoNotBlend = 1,
+    };
+    BlendingMethod blending_method { BlendingMethod::UseAlphaBlending };
+
+    enum class DisposalMethod {
+        DoNotDispose = 0,
+        DisposeToBackgroundColor = 1,
+    };
+    DisposalMethod disposal_method { DisposalMethod::DoNotDispose };
+
+    ReadonlyBytes frame_data;
+};
+
+}

Userland/Libraries/LibGfx/ImageFormats/WebPWriter.cpp

@@ -11,6 +11,7 @@
 #include <AK/Debug.h>
 #include <LibCompress/DeflateTables.h>
 #include <LibGfx/Bitmap.h>
+#include <LibGfx/ImageFormats/WebPShared.h>
 #include <LibGfx/ImageFormats/WebPWriter.h>
 #include <LibRIFF/RIFF.h>
 
@@ -189,16 +190,6 @@ static ErrorOr<void> write_VP8L_image_data(Stream& stream, Bitmap const& bitmap)
     return {};
 }
 
-struct VP8XHeader {
-    bool has_icc { false };
-    bool has_alpha { false };
-    bool has_exif { false };
-    bool has_xmp { false };
-    bool has_animation { false };
-    u32 width { 0 };
-    u32 height { 0 };
-};
-
 static u8 vp8x_flags_from_header(VP8XHeader const& header)
 {
     u8 flags = 0;
@@ -362,28 +353,6 @@ static ErrorOr<void> align_to_two(SeekableStream& stream)
     return {};
 }
 
-struct ANMFChunk {
-    u32 frame_x { 0 };
-    u32 frame_y { 0 };
-    u32 frame_width { 0 };
-    u32 frame_height { 0 };
-    u32 frame_duration_in_milliseconds { 0 };
-
-    enum class BlendingMethod {
-        UseAlphaBlending = 0,
-        DoNotBlend = 1,
-    };
-    BlendingMethod blending_method { BlendingMethod::UseAlphaBlending };
-
-    enum class DisposalMethod {
-        DoNotDispose = 0,
-        DisposeToBackgroundColor = 1,
-    };
-    DisposalMethod disposal_method { DisposalMethod::DoNotDispose };
-
-    ReadonlyBytes frame_data;
-};
-
 static ErrorOr<void> write_ANMF_chunk(Stream& stream, ANMFChunk const& chunk)
 {
     if (chunk.frame_width > (1 << 24) || chunk.frame_height > (1 << 24))
@@ -510,11 +479,6 @@ ErrorOr<void> WebPAnimationWriter::set_alpha_bit_in_header()
     return {};
 }
 
-struct ANIMChunk {
-    u32 background_color { 0 };
-    u16 loop_count { 0 };
-};
-
 static ErrorOr<void> write_ANIM_chunk(Stream& stream, ANIMChunk const& chunk)
 {
     TRY(write_chunk_header(stream, "ANIM"sv, 6)); // Size of the ANIM chunk.