Render SVGs with librsvg

.github/workflows/macos.yml

@@ -17,12 +17,19 @@ jobs:
           brew install libdeflate libsixel
           brew install ffmpeg jpeg-turbo libexif libpng
           brew install openslide
+          brew install librsvg cairo
           brew install pandoc
+
       - name: Get the Source
         uses: actions/checkout@v3
+
       - name: Build timg
         run: |
           mkdir build
           cd build
           cmake .. -DWITH_VIDEO_DECODING=On -DWITH_VIDEO_DEVICE=On -DWITH_OPENSLIDE_SUPPORT=On
           make -k
+
+      - name: Print timg Version string
+        run: |
+          build/src/timg --version

.github/workflows/ubuntu.yml

@@ -36,7 +36,7 @@ jobs:
         run: |
           mkdir build-limitdep
           cd build-limitdep
-          cmake .. -DWITH_VIDEO_DECODING=Off -DWITH_VIDEO_DEVICE=Off -DWITH_OPENSLIDE_SUPPORT=Off -DWITH_GRAPHICSMAGICK=Off -DWITH_TURBOJPEG=Off -DWITH_LIBSIXEL=Off
+          cmake .. -DWITH_VIDEO_DECODING=Off -DWITH_VIDEO_DEVICE=Off -DWITH_OPENSLIDE_SUPPORT=Off -DWITH_GRAPHICSMAGICK=Off -DWITH_TURBOJPEG=Off -DWITH_RSVG=Off -DWITH_LIBSIXEL=Off
           make -k
 
       - name: Install Full Dependencies
@@ -45,6 +45,7 @@ jobs:
           sudo apt install libgraphicsmagick++-dev
           sudo apt install libturbojpeg-dev libexif-dev
           sudo apt install libsixel-dev
+          sudo apt install librsvg2-dev libcairo-dev
           sudo apt install libavcodec-dev libavformat-dev libavdevice-dev
           sudo apt install libopenslide-dev
           sudo apt install pandoc
@@ -53,9 +54,18 @@ jobs:
         run: |
           mkdir build
           cd build
-          cmake .. -DWITH_VIDEO_DECODING=On -DWITH_VIDEO_DEVICE=On -DWITH_OPENSLIDE_SUPPORT=On -DWITH_STB_IMAGE=On -DWITH_LIBSIXEL=On
+          cmake .. -DWITH_VIDEO_DECODING=On -DWITH_VIDEO_DEVICE=On -DWITH_OPENSLIDE_SUPPORT=On -DWITH_STB_IMAGE=On -DWITH_RSVG=On -DWITH_LIBSIXEL=On
           make -k
 
+      - name: Print timg Version string
+        run: |
+          echo "------------------- Limited dependency version string --------"
+          build-limitdep/src/timg --version
+          echo
+
+          echo "------------------- All dependencies version string ----------"
+          build/src/timg --version
+
   CodeFormatting:
     if: false   # currently, there is no clang-format-13 in ubuntu latest
     runs-on: ubuntu-latest
@@ -131,6 +141,7 @@ jobs:
           sudo apt install cmake git g++ clang pkg-config
           sudo apt install libswscale-dev libavutil-dev libdeflate-dev
           sudo apt install libturbojpeg-dev libexif-dev
+          sudo apt install librsvg2-dev libcairo-dev
           sudo apt install libsixel-dev
           sudo apt install pandoc
 
@@ -144,6 +155,7 @@ jobs:
           # also check apt to include in .github/conf/AppImageBuilder.yml
           ./.github/bin/prepare-app-image.sh \
              -DWITH_GRAPHICSMAGICK=Off \
+             -DWITH_RSVG=On \
              -DWITH_VIDEO_DECODING=Off \
              -DWITH_VIDEO_DEVICE=Off \
              -DWITH_OPENSLIDE_SUPPORT=Off \

CMakeLists.txt

@@ -4,18 +4,21 @@ project(timg VERSION 1.5.3 LANGUAGES CXX)
 
 option(WITH_VIDEO_DECODING "Enables video decoding feature" ON)
 option(WITH_VIDEO_DEVICE "Enables reading videos from devices e.g. v4l2 (requires WITH_VIDEO_DECODING)" ON)
-option(WITH_OPENSLIDE_SUPPORT "Enables support to scientific OpenSlide formats" OFF)
 
 # Options that should be typically on, but could be disabled for special
 # applications where less dependencies are required
 option(WITH_GRAPHICSMAGICK "Enable general image loading with Graphicsmagick. You typically want this." ON)
 option(WITH_TURBOJPEG "Optimized JPEG loading. You typically want this." ON)
-option(WITH_LIBSIXEL "Provide sixel output which is supported by some older terminals such as xterm" ON)
-
+option(WITH_RSVG "Use librsvg to open SVG images." ON)
 option(WITH_STB_IMAGE "Use STB image, a self-contained albeit limited image loading and lower quality. Use if WITH_GRAPHICSMAGICK is not possible and want to limit dependencies. Default on to be used as fallback." ON)
-
 option(WITH_QOI_IMAGE "QOI image format" ON)
 
+# Compile-time option for specialized
+option(WITH_OPENSLIDE_SUPPORT "Enables support to scientific OpenSlide formats" OFF)
+
+# Output formats
+option(WITH_LIBSIXEL "Provide sixel output which is supported by some older terminals such as xterm" ON)
+
 # Note: The version string can be ammended with -DDISTRIBUTION_VERSION, see src/timg-version.h.in
 option(TIMG_VERSION_FROM_GIT "Get the program version from the git repository" ON)
 
@@ -52,6 +55,11 @@ if(WITH_GRAPHICSMAGICK)
   pkg_check_modules(GRAPHICSMAGICKXX IMPORTED_TARGET REQUIRED GraphicsMagick++)
 endif()
 
+if(WITH_RSVG)
+  pkg_check_modules(RSVG REQUIRED IMPORTED_TARGET librsvg-2.0)
+  pkg_check_modules(CAIRO REQUIRED IMPORTED_TARGET cairo)
+endif()
+
 if(WITH_OPENSLIDE_SUPPORT)
   pkg_check_modules(OPENSLIDE IMPORTED_TARGET REQUIRED openslide)
   pkg_check_modules(AVUTIL REQUIRED IMPORTED_TARGET libavutil)

README.md

@@ -480,10 +480,11 @@ brew install timg
 #### Use AppImage
 
 The [timg release page](https://github.com/hzeller/timg/releases/latest) also
-has a minimal binary in the [AppImage package format][AppImage].
-To keep the size small, it does not include video decoding or some more
-fancy image formats. It is good for many contexts, but for a full-featured
-binary, use one from your distribution or build from source.
+has a _minimal_ binary in the [AppImage package format][AppImage].
+To keep the size small, it does _not_ include video decoding or some more
+fancy image formats. It is good for many contexts or if you want to try out
+`timg`, but for a full-featured binary, use one from your distribution or
+build from source.
 
 ### Build and Install from source
 
@@ -557,6 +558,9 @@ compile-time choices:
     typically want this **ON** (default).
   * **`WITH_TURBOJPEG`** If enabled, uses this for faster jpeg file loading.
      You typically want this **ON** (default).
+  * **`WITH_RSVG`** High-quality SVG renderer. Needs librsvg and cairo.
+    If not compiled-in, will fallback to GraphicsMagick, but that typically
+    results in lower quality renderings. Typically want this **ON** (default).
   * **`WITH_OPENSLIDE_SUPPORT`** Openslide is an image format used in scientific
     applications. Rarely used, so default off, switch ON if needed.
   * **`WITH_QOI_IMAGE`** Allow decoding of Quite Ok Image format [QOI]. Small

shell.nix

@@ -16,6 +16,13 @@ pkgs.mkShell {
        ffmpeg
        libexif
        libsixel
+       librsvg cairo
+
+       # Don't include qoi and stb by default to see if the cmake
+       # fallback to third_party/ works.
+       #qoi
+       #stb
+
        openslide
        pandoc
        clang-tools_13  # clang-format

src/CMakeLists.txt

@@ -57,6 +57,12 @@ if(WITH_GRAPHICSMAGICK)
   target_link_libraries(timg PkgConfig::GRAPHICSMAGICKXX)
 endif()
 
+if(WITH_RSVG)
+  target_sources(timg PUBLIC svg-image-source.h svg-image-source.cc)
+  target_compile_definitions(timg PUBLIC WITH_TIMG_RSVG)
+  target_link_libraries(timg PkgConfig::RSVG PkgConfig::CAIRO)
+endif()
+
 if(WITH_TURBOJPEG)
   target_sources(timg PUBLIC jpeg-source.h jpeg-source.cc)
   target_compile_definitions(timg PUBLIC WITH_TIMG_JPEG)

src/framebuffer.h

@@ -26,7 +26,7 @@
 namespace timg {
 struct rgba_t {
     uint8_t r, g, b;  // Color components, gamma corrected (non-linear)
-    uint8_t a;        // Alpha channel. Linear.
+    uint8_t a;        // Alpha channel. Linear. [transparent..opaque]=0..255
 
     inline bool operator==(const rgba_t &that) const {
         // Using memcmp() slower, so force uint-compare with type-punning.

src/image-source.cc

@@ -34,6 +34,7 @@
 #include "openslide-source.h"
 #include "qoi-image-source.h"
 #include "stb-image-source.h"
+#include "svg-image-source.h"
 #include "video-display.h"
 
 namespace timg {
@@ -176,6 +177,13 @@ ImageSource *ImageSource::Create(const std::string &filename,
         }
 #endif
 
+#ifdef WITH_TIMG_RSVG
+        result.reset(new SVGImageSource(filename));
+        if (result->LoadAndScale(options, frame_offset, frame_count)) {
+            return result.release();
+        }
+#endif
+
 #ifdef WITH_TIMG_GRPAPHICSMAGICK
         result.reset(new ImageLoader(filename));
         if (result->LoadAndScale(options, frame_offset, frame_count)) {

src/svg-image-source.cc

@@ -0,0 +1,106 @@
+// -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; -*-
+// (c) 2023 Henner Zeller <h.zeller@acm.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation version 2.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://gnu.org/licenses/gpl-2.0.txt>
+
+#include "svg-image-source.h"
+
+#include <cairo.h>
+#include <librsvg/rsvg.h>
+#include <stdlib.h>
+
+#include "framebuffer.h"
+
+namespace timg {
+
+std::string SVGImageSource::FormatTitle(
+    const std::string &format_string) const {
+    return FormatFromParameters(format_string, filename_, (int)orig_width_,
+                                (int)orig_height_, "svg");
+}
+
+bool SVGImageSource::LoadAndScale(const DisplayOptions &opts, int, int) {
+    options_        = opts;
+    RsvgHandle *svg = rsvg_handle_new_from_file(filename_.c_str(), nullptr);
+    if (!svg) return false;
+
+    RsvgRectangle viewbox;
+    gboolean out_has_width, out_has_height, out_has_viewbox;
+    RsvgLength svg_width, svg_height;
+    rsvg_handle_get_intrinsic_dimensions(svg, &out_has_width, &svg_width,
+                                         &out_has_height, &svg_height,
+                                         &out_has_viewbox, &viewbox);
+    if (out_has_viewbox) {
+        orig_width_  = viewbox.width;
+        orig_height_ = viewbox.height;
+    }
+    else if (out_has_width && out_has_height) {
+        // We ignore the unit, but this will still result in proper aspect ratio
+        orig_width_  = svg_width.length;
+        orig_height_ = svg_height.length;
+    }
+
+    int target_width;
+    int target_height;
+    CalcScaleToFitDisplay(orig_width_, orig_height_, opts, false, &target_width,
+                          &target_height);
+
+    const auto kCairoFormat = CAIRO_FORMAT_ARGB32;
+    int stride = cairo_format_stride_for_width(kCairoFormat, target_width);
+    image_.reset(new timg::Framebuffer(stride / 4, target_height));
+
+    cairo_surface_t *surface = cairo_image_surface_create_for_data(
+        (uint8_t *)image_->begin(), kCairoFormat, target_width, target_height,
+        stride);
+    cairo_t *cr = cairo_create(surface);
+
+    RsvgRectangle viewport = {
+        .x      = 0.0,
+        .y      = 0.0,
+        .width  = (double)target_width,
+        .height = (double)target_height,
+    };
+
+    bool success = rsvg_handle_render_document(svg, cr, &viewport, nullptr);
+    cairo_destroy(cr);
+    cairo_surface_destroy(surface);
+    g_object_unref(svg);
+
+    // TODO: for non-1:1 aspect ratio of the output (e.g. pixelation=quarter),
+    //       the resulting aspect ratio is squished, as we have to do the
+    //       distortion ourself.
+    // TODO: if (int(stride / sizeof(rgba_t)) != target_width) : copy over
+
+    // If requested, merge background with pattern.
+    image_->AlphaComposeBackground(
+        options_.bgcolor_getter, options_.bg_pattern_color,
+        options_.pattern_size * options_.cell_x_px,
+        options_.pattern_size * options_.cell_y_px / 2);
+
+    return success;
+}
+
+int SVGImageSource::IndentationIfCentered(
+    const timg::Framebuffer &image) const {
+    return options_.center_horizontally ? (options_.width - image.width()) / 2
+                                        : 0;
+}
+
+void SVGImageSource::SendFrames(const Duration &duration, int loops,
+                                const volatile sig_atomic_t &interrupt_received,
+                                const Renderer::WriteFramebufferFun &sink) {
+    sink(IndentationIfCentered(*image_), 0, *image_, SeqType::FrameImmediate,
+         {});
+}
+
+}  // namespace timg

src/svg-image-source.h

@@ -0,0 +1,50 @@
+// -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; -*-
+// (c) 2023 Henner Zeller <h.zeller@acm.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation version 2.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://gnu.org/licenses/gpl-2.0.txt>
+
+#ifndef SVG_SOURCE_H_
+#define SVG_SOURCE_H_
+
+#include <memory>
+
+#include "display-options.h"
+#include "image-source.h"
+#include "terminal-canvas.h"
+
+namespace timg {
+class SVGImageSource final : public ImageSource {
+public:
+    explicit SVGImageSource(const std::string &filename)
+        : ImageSource(filename) {}
+
+    bool LoadAndScale(const DisplayOptions &options, int frame_offset,
+                      int frame_count) final;
+
+    void SendFrames(const Duration &duration, int loops,
+                    const volatile sig_atomic_t &interrupt_received,
+                    const Renderer::WriteFramebufferFun &sink) final;
+
+    std::string FormatTitle(const std::string &format_string) const final;
+
+private:
+    int IndentationIfCentered(const timg::Framebuffer &image) const;
+
+    DisplayOptions options_;
+    double orig_width_, orig_height_;
+    std::unique_ptr<timg::Framebuffer> image_;
+};
+
+}  // namespace timg
+
+#endif  // QOI_SOURCE_H_