Expose a C API

examples/CMakeLists.txt

@@ -140,6 +140,44 @@ function(add_example name)
 
 endfunction()
 
+function(add_c_example name)
+   if (APPLE)
+      add_executable(
+         ${name}-c MACOSX_BUNDLE
+         ${name}.c
+         ${artist_fonts}
+         ${${name}_images}
+      )
+
+      message(STATUS ${CMAKE_CURRENT_SOURCE_DIR})
+
+      target_include_directories(
+         ${name}-c
+         PUBLIC
+         ${CMAKE_CURRENT_LIST_DIR}/../lib/include
+      )
+
+      set_target_properties(
+         ${name}
+         PROPERTIES
+         MACOSX_BUNDLE_INFO_PLIST
+         ${CMAKE_CURRENT_LIST_DIR}/../resources/macos/plist.in
+      )
+
+      target_link_options(${name} PRIVATE -framework AppKit)
+
+      set_source_files_properties(
+         ${artist_fonts}
+         ${${name}_images}
+         PROPERTIES
+         MACOSX_PACKAGE_LOCATION Resources
+      )
+   else()
+      message(FATAL_ERROR "Unsupported platform for artist C API!")
+   endif()
+
+endfunction()
+
 set(space_images
    ${CMAKE_CURRENT_LIST_DIR}/images/space.jpg
 )
@@ -159,3 +197,4 @@ add_example(paths)
 add_example(shadow)
 add_example(chessboard)
 
+add_c_example(paths)

examples/paths.c

@@ -0,0 +1,79 @@
+#include <artist/c/canvas.h>
+
+void stroke_fill(canvas* cnv, path* p, color fill_c, color stroke_c) {
+   artist_canvas_add_path(cnv, p);
+   artist_canvas_fill_color(cnv, fill_c);
+   artist_canvas_stroke_color(cnv, stroke_c);
+   artist_canvas_fill(cnv);
+   artist_canvas_line_width(cnv, 5);
+   artist_canvas_add_path(cnv, p);
+   artist_canvas_stroke(cnv);
+}
+
+void stroke(canvas* cnv, path* p, color stroke_c) {
+   artist_canvas_add_path(cnv, p);
+   artist_canvas_stroke_color(cnv, stroke_c);
+   artist_canvas_line_width(cnv, 5);
+   artist_canvas_stroke(cnv);
+}
+
+void dot(canvas* cnv, float x, float y) {
+   artist_canvas_add_circle(cnv, x, y, 10);
+   artist_canvas_fill_color(cnv, artist_color_opacity(COLOR_WHITE, 0.5));
+   artist_canvas_fill(cnv);
+}
+
+int main(int argc, char const *argv[])
+{
+   image* buffer = artist_image_create(400, 300);
+   offscreen_image* surface = artist_offscreen_image_create(buffer);
+   canvas* cnv = artist_offscreen_image_context(surface);
+
+   // These paths are defined using SVG-style strings lifted off the
+   // W3C SVG documentation: https://www.w3.org/TR/SVG/paths.html
+
+   // TODO: auto save = cnv.new_state();
+   artist_canvas_scale(cnv, 0.5, 0.5);
+
+   artist_canvas_translate(cnv, -40, 0);
+   path* p1 = artist_path_create_from_svg("M 100 100 L 300 100 L 200 300 z");
+   stroke_fill(cnv, p1, artist_color_opacity(COLOR_GREEN, 0.5), COLOR_IVORY);
+
+   artist_canvas_translate(cnv, 220, 0);
+   path* p2 = artist_path_create_from_svg("M100,200 C100,100 250,100 250,200 S400,300 400,200");
+   stroke(cnv, p2, COLOR_LIGHT_SKY_BLUE);
+
+   artist_canvas_translate(cnv, -150, 250);
+   path* p3 = artist_path_create_from_svg("M200,300 Q400,50 600,300 T1000,300");
+   stroke(cnv, p3, COLOR_LIGHT_SKY_BLUE);
+
+   path* p4 = artist_path_create_from_svg("M200,300 L400,50 L600,300 L800,550 L1000,300");
+   stroke(cnv, p4, artist_color_opacity(COLOR_LIGHT_GRAY, 0.5));
+   dot(cnv, 200, 300);
+   dot(cnv, 600, 300);
+   dot(cnv, 1000, 300);
+   dot(cnv, 400, 50);
+   dot(cnv, 800, 550);
+   artist_canvas_translate(cnv, 150, -250);
+
+   artist_canvas_translate(cnv, 350, 0);
+   path* p5 = artist_path_create_from_svg("M300,200 h-150 a150,150 0 1,0 150,-150 z");
+   stroke_fill(cnv, p5, artist_color_opacity(COLOR_RED, 0.8), COLOR_IVORY);
+
+   path* p6 = artist_path_create_from_svg("M275,175 v-150 a150,150 0 0,0 -150,150 z");
+   stroke_fill(cnv, p6, artist_color_opacity(COLOR_BLUE, 0.8), COLOR_IVORY);
+
+   artist_canvas_translate(cnv, -350, 200);
+   path* p7 = artist_path_create_from_svg(
+      "M600,350 l 50,-25"
+      "a25,25 -30 0,1 50,-25 l 50,-25"
+      "a25,50 -30 0,1 50,-25 l 50,-25"
+      "a25,75 -30 0,1 50,-25 l 50,-25"
+      "a25,100 -30 0,1 50,-25 l 50,-25"
+   );
+   stroke(p7, COLOR_IVORY);
+
+   artist_image_save_png(buffer, create);
+
+   return 0;
+}

lib/CMakeLists.txt

@@ -122,6 +122,16 @@ set(ARTIST_SOURCES
    src/artist/rect.cpp
    src/artist/resources.cpp
    src/artist/svg_path.cpp
+   src/artist/c/affine_transform.cpp
+   src/artist/c/canvas.cpp
+   src/artist/c/circle.cpp
+   src/artist/c/color.cpp
+   src/artist/c/font.cpp
+   src/artist/c/image.cpp
+   src/artist/c/path.cpp
+   src/artist/c/rect.cpp
+   src/artist/c/strings.cpp
+   src/artist/c/text_layout.cpp
 )
 
 set(ARTIST_HEADERS

lib/include/artist/affine_transform.hpp

@@ -8,10 +8,13 @@
 
 #include <cmath>
 #include <artist/point.hpp>
+#include <artist/c/affine_transform.h>
+
+typedef affine_transform c_affine_transform;
 
 namespace cycfi::artist
 {
-   struct affine_transform
+   struct affine_transform : c_affine_transform
    {
       constexpr bool                   is_identity() const;
       constexpr affine_transform       translate(double tx, double ty) const;
@@ -36,7 +39,7 @@ namespace cycfi::artist
       double ty   = 0.0;
    };
 
-   constexpr affine_transform affine_identity;
+   constexpr affine_transform affine_identity = { 1.0, 0.0, 0.0, 1.0, 0.0, 0.0 };
 
    constexpr affine_transform make_translation(double tx, double ty);
    constexpr affine_transform make_scale(double sx, double sy);

lib/include/artist/c/affine_transform.h

@@ -0,0 +1,52 @@
+/*=============================================================================
+   Copyright (c) 2021 Chance Snow, Joel de Guzman
+
+   Distributed under the MIT License [ https://opensource.org/licenses/MIT ]
+=============================================================================*/
+#ifndef __ARTIST_AFFINE_TRANSFORM_H
+#define __ARTIST_AFFINE_TRANSFORM_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "point.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+   typedef struct {
+      double a;
+      double b;
+      double c;
+      double d;
+      double tx;
+      double ty;
+   } affine_transform;
+
+   affine_transform           artist_affine_transform_identity();
+   bool                       artist_affine_transform_is_identity(affine_transform t);
+   affine_transform           artist_affine_transform_translate(affine_transform t, double tx, double ty);
+   affine_transform           artist_affine_transform_scale(affine_transform t, double sx, double sy);
+   affine_transform           artist_affine_transform_scale_square(affine_transform t, double sc);
+   inline affine_transform    artist_affine_transform_rotate(affine_transform t, double rad);
+   inline affine_transform    artist_affine_transform_skew(affine_transform t, double sx, double sy);
+   affine_transform           artist_affine_transform_invert(affine_transform t);
+
+   point                      artist_affine_transform_apply_pt(affine_transform t, point p);
+   point                      artist_affine_transform_apply(affine_transform t, float x, float y);
+
+   //                               template <std::size_t N>
+   // void                       apply(point p[N]) const;
+   void                       artist_affine_transform_apply_points(affine_transform t, point* p, size_t n);
+
+   affine_transform           artist_affine_transform_make_translation(double tx, double ty);
+   affine_transform           artist_affine_transform_make_scale(double sx, double sy);
+   affine_transform           artist_affine_transform_make_scale_square(double sc);
+   inline affine_transform    artist_affine_transform_make_rotation(double rad);
+   inline affine_transform    artist_affine_transform_make_skew(double sx, double sy);
+
+#ifdef __cplusplus
+}
+#endif
+#endif

lib/include/artist/c/artist.h

@@ -0,0 +1,25 @@
+/*=============================================================================
+   Copyright (c) 2021 Chance Snow, Joel de Guzman
+
+   Distributed under the MIT License [ https://opensource.org/licenses/MIT ]
+=============================================================================*/
+#ifndef __ARTIST_H
+#define __ARTIST_H
+
+////////////////////////////////////////////////////////////////////////////
+// Amalgamated C API
+////////////////////////////////////////////////////////////////////////////
+
+#include "canvas.h"
+#include "color.h"
+#include "circle.h"
+#include "image.h"
+#include "font.h"
+#include "path.h"
+#include "point.h"
+#include "rect.h"
+#include "strings.h"
+#include "text_layout.h"
+#include "affine_transform.h"
+
+#endif