karm-image: Basic gif metadata extraction.

src/apps/hideo-images/main.cpp

@@ -35,6 +35,10 @@ Async::Task<> entryPointAsync(Sys::Context &ctx) {
     if (args.len()) {
         auto url = co_try$(Mime::parseUrlOrPath(args[0]));
         image = Image::load(url);
+
+        if (not image) {
+            logError("Failed to load image: {}", image.none());
+        }
     }
 
     co_return Ui::runApp(ctx, Hideo::Images::app(image));

src/apps/hideo-images/viewer.cpp

@@ -25,7 +25,7 @@ Ui::Child viewer(State const &state) {
 
 Ui::Child viewerPreview(State const &state) {
     if (not state.image)
-        return Kr::errorPage(Mdi::ALERT_DECAGRAM, "No Image"s, "Unable to display this image."s);
+        return Kr::errorPage(Mdi::ALERT_DECAGRAM, "Unable to display this image."s, Str{state.image.none().msg()});
 
     return Ui::image(state.image.unwrap()) |
            Ui::box({

src/libs/karm-image/bmp/decoder.cpp

@@ -9,15 +9,15 @@ Res<Decoder> Decoder::init(Bytes slice) {
 
     Decoder dec{};
     Io::BScan s{slice};
-    try$(dec.readHeader(s));
-    try$(dec.readInfoHeader(s));
+    try$(dec._readHeader(s));
+    try$(dec._readInfoHeader(s));
     try$(dec._readPalette(s));
     try$(dec._readPixels(s));
 
     return Ok(dec);
 }
 
-Res<> Decoder::readHeader(Io::BScan &s) {
+Res<> Decoder::_readHeader(Io::BScan &s) {
     if (s.rem() < 54) {
         return Error::invalidData("image too small");
     }
@@ -30,7 +30,7 @@ Res<> Decoder::readHeader(Io::BScan &s) {
     return Ok();
 }
 
-Res<> Decoder::readInfoHeader(Io::BScan &s) {
+Res<> Decoder::_readInfoHeader(Io::BScan &s) {
     auto start = s.tell();
     auto size = s.nextU32le(); // header size
     if (size < 40) {

src/libs/karm-image/bmp/decoder.h

@@ -1,6 +1,6 @@
 #pragma once
 
-// BMP image decoder/encoder
+// BMP image decoder
 // References:
 //  - https://en.wikipedia.org/wiki/BMP_file_format
 //  - https://docs.microsoft.com/en-us/windows/win32/gdi/bitmap-storage
@@ -10,7 +10,6 @@
 #include <karm-base/vec.h>
 #include <karm-gfx/buffer.h>
 #include <karm-io/bscan.h>
-#include <karm-io/emit.h>
 #include <karm-logger/logger.h>
 
 namespace Bmp {
@@ -31,7 +30,7 @@ struct Decoder {
 
     usize _dataOffset;
 
-    Res<> readHeader(Io::BScan &s);
+    Res<> _readHeader(Io::BScan &s);
 
     isize _width;
     isize _height;
@@ -53,7 +52,7 @@ struct Decoder {
 
     usize _numsColors;
 
-    Res<> readInfoHeader(Io::BScan &s);
+    Res<> _readInfoHeader(Io::BScan &s);
 
     // MARK: Palette -----------------------------------------------------------
 

src/libs/karm-image/gif/decoder.h

@@ -0,0 +1,74 @@
+#pragma once
+
+// GIF Image decoder
+// References:
+//  - https://www.w3.org/Graphics/GIF/spec-gif89a.txt
+
+#include <karm-gfx/buffer.h>
+#include <karm-io/bscan.h>
+
+namespace Gif {
+
+struct Decoder {
+    struct Header {
+        Array<u8, 6> signature;
+    };
+
+    struct LogicalScreenDescriptor {
+        u16le width;
+        u16le height;
+        u8 packed;
+        u8 backgroundColorIndex;
+        u8 pixelAspectRatio;
+    };
+
+    static bool sniff(Bytes slice) {
+        bool isGif = slice.len() >= 6 and
+                     slice[0] == 'G' and
+                     slice[1] == 'I' and
+                     slice[2] == 'F';
+
+        bool isGif89a = slice.len() >= 6 and
+                        slice[3] == '8' and
+                        slice[4] == '9' and
+                        slice[5] == 'a';
+
+        bool isGif87a = slice.len() >= 6 and
+                        slice[3] == '8' and
+                        slice[4] == '7' and
+                        slice[5] == 'a';
+
+        return isGif and (isGif89a or isGif87a);
+    }
+
+    static Res<Decoder> init(Bytes slice) {
+        if (not sniff(slice))
+            return Error::invalidData("invalid signature");
+
+        Decoder dec{};
+        Io::BScan scan{slice};
+
+        Header header{};
+        scan.readTo(&header);
+
+        LogicalScreenDescriptor lsd{};
+        scan.readTo(&lsd);
+
+        dec._size = {lsd.width, lsd.height};
+
+        return Ok(dec);
+    }
+
+    Math::Vec2i _size;
+
+    isize width() const { return _size.x; }
+
+    isize height() const { return _size.y; }
+
+    Res<> decode(Gfx::MutPixels pixels) {
+        (void)pixels;
+        return Ok();
+    }
+};
+
+} // namespace Gif

src/libs/karm-image/gif/manifest.json

@@ -0,0 +1,12 @@
+{
+    "$schema": "https://schemas.cute.engineering/stable/cutekit.manifest.component.v1",
+    "id": "karm-image.gif",
+    "type": "lib",
+    "description": "GIF image decoding and encoding",
+    "props": {
+        "cpp-excluded": true
+    },
+    "requires": [
+        "karm-base"
+    ]
+}

src/libs/karm-image/loader.cpp

@@ -1,6 +1,7 @@
 #include <karm-sys/file.h>
 
 #include "bmp/decoder.h"
+#include "gif/decoder.h"
 #include "jpeg/decoder.h"
 #include "png/decoder.h"
 #include "qoi/decoder.h"
@@ -39,13 +40,20 @@ static Res<Picture> loadJpeg(Bytes bytes) {
     return Ok(img);
 }
 
-static Res<Picture> load(Bytes bytes) {
+static Res<Picture> loadTga(Bytes bytes) {
     auto tga = try$(Tga::Decoder::init(bytes));
     auto img = Gfx::Surface::alloc({tga.width(), tga.height()});
     try$(tga.decode(*img));
     return Ok(img);
 }
 
+static Res<Picture> loadGif(Bytes bytes) {
+    auto gif = try$(Gif::Decoder::init(bytes));
+    auto img = Gfx::Surface::alloc({gif.width(), gif.height()});
+    try$(gif.decode(*img));
+    return Ok(img);
+}
+
 Res<Picture> load(Sys::Mmap &&map) {
     if (Bmp::Decoder::sniff(map.bytes())) {
         return loadBmp(map.bytes());
@@ -56,7 +64,9 @@ Res<Picture> load(Sys::Mmap &&map) {
     } else if (Jpeg::Decoder::sniff(map.bytes())) {
         return loadJpeg(map.bytes());
     } else if (Tga::Decoder::sniff(map.bytes())) {
-        return load(map.bytes());
+        return loadTga(map.bytes());
+    } else if (Gif::Decoder::sniff(map.bytes())) {
+        return loadGif(map.bytes());
     } else {
         return Error::invalidData("unknown image format");
     }

src/libs/karm-image/manifest.json

@@ -9,6 +9,7 @@
         "karm-image.png",
         "karm-image.qoi",
         "karm-image.tga",
+        "karm-image.gif",
         "karm-gfx",
         "karm-sys",
         "karm-logger"