Tools: Add SDF-generation tool and 4x font SDF

CMakeLists.txt

@@ -85,6 +85,7 @@ if(NOT LIBMGBA_ONLY)
 	set(BUILD_GLES2 ON CACHE BOOL "Build with OpenGL|ES 2")
 	set(BUILD_GLES3 ON CACHE BOOL "Build with OpenGL|ES 3")
 	set(BUILD_DOCGEN OFF CACHE BOOL "Build the scripting API documentation generator")
+	set(BUILD_MAINTAINER_TOOLS OFF CACHE BOOL "Build tools only useful for maintainers")
 	set(USE_EPOXY ON CACHE STRING "Build with libepoxy")
 	set(DISABLE_DEPS OFF CACHE BOOL "Build without dependencies")
 	set(DISTBUILD OFF CACHE BOOL "Build distribution packages")
@@ -93,6 +94,7 @@ if(NOT LIBMGBA_ONLY)
 		mark_as_advanced(WIN32_UNIX_PATHS)
 	endif()
 	mark_as_advanced(BUILD_DOCGEN)
+	mark_as_advanced(BUILD_MAINTAINER_TOOLS)
 else()
 	set(DISABLE_FRONTENDS ON)
 	set(DISABLE_DEPS ON)
@@ -1045,6 +1047,11 @@ if(ENABLE_SCRIPTING AND BUILD_DOCGEN)
 	target_link_libraries(docgen ${OS_LIB} ${PLATFORM_LIBRARY} ${BINARY_NAME})
 endif()
 
+if(BUILD_MAINTAINER_TOOLS)
+	add_executable(font-sdf-tool ${CMAKE_CURRENT_SOURCE_DIR}/src/tools/font-sdf.c ${CMAKE_CURRENT_SOURCE_DIR}/src/util/gui/font-metrics.c)
+	target_link_libraries(font-sdf-tool ${OS_LIB} ${PLATFORM_LIBRARY} ${BINARY_NAME})
+endif()
+
 if(BUILD_SDL)
 	add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/src/platform/sdl ${CMAKE_CURRENT_BINARY_DIR}/sdl)
 endif()

include/mgba-util/gui/font-metrics.h

@@ -6,9 +6,10 @@
 #ifndef DEFAULT_FONT_METRICS_H
 #define DEFAULT_FONT_METRICS_H
 
+#include <mgba-util/dllexports.h>
 #include <mgba-util/gui/font.h>
 
-extern struct GUIFontGlyphMetric defaultFontMetrics[];
+extern const struct GUIFontGlyphMetric defaultFontMetrics[128];
-extern struct GUIIconMetric defaultIconMetrics[];
+extern const struct GUIIconMetric defaultIconMetrics[GUI_ICON_MAX];
 
 #endif

src/tools/font-sdf.c

@@ -0,0 +1,136 @@
+/* Copyright (c) 2013-2023 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include <mgba-util/image.h>
+#include <mgba-util/gui/font-metrics.h>
+#include <mgba-util/math.h>
+
+void createSdf(const struct mImage* src, struct mImage* dst, int x, int y, int w, int h) {
+	int i, j, ii, jj, z;
+
+	static const int kernel[] = {
+		11, 9, 8, 9, 11,
+		 9, 6, 4, 6,  9,
+		 8, 4, 0, 4,  8,
+		 9, 6, 4, 6,  9,
+		11, 9, 8, 9, 11,
+	};
+	const int* kc = &kernel[12];
+
+	for (j = y; j < y + h; ++j) {
+		for (i = x; i < x + w; ++i) {
+			if (mImageGetPixel(src, i, j) & 0xFFFFFF) {
+				mImageSetPixelRaw(dst, i, j, 0xFF);
+			} else {
+				mImageSetPixelRaw(dst, i, j, 1);		
+			}
+		}
+	}
+
+	for (z = 0; z < 16; ++z) {
+		int left = w * h;
+		for (j = y; j < y + h; ++j) {
+			for (i = x; i < x + w; ++i) {
+				int raw = mImageGetPixelRaw(dst, i, j) - 0x80;
+				int neighbors = raw;
+				for (jj = -2; jj < 3; ++jj) {
+					for (ii = -2; ii < 3; ++ii) {
+						if (!ii && !jj) {
+							continue;
+						}
+						if (i + ii - x < 0 || j + jj - y < 0) {
+							continue;
+						}
+						if (i + ii - x >= w || j + jj - y >= h) {
+							continue;
+						}
+						int neighbor = mImageGetPixelRaw(dst, i + ii, j + jj) - 0x80;
+						if (raw > 0) {
+							if (neighbor < 0) {
+								if ((!ii && (jj == -1 || jj == 1)) || (!jj && (ii == -1 || ii == 1))) {
+									neighbors = 1;
+									jj = 5;
+									break;
+								}
+								continue;
+							}
+							if (neighbor == 0x7F) {
+								continue;
+							}
+							if (neighbor + kc[ii + jj * 5] < neighbors) {
+								neighbors = neighbor + kc[ii + jj * 5];
+							}
+						} else if (raw < 0) {
+							if (neighbor > 0) {
+								if ((!ii && (jj == -1 || jj == 1)) || (!jj && (ii == -1 || ii == 1))) {
+									neighbors = -4;
+									jj = 5;
+									break;
+								}
+								continue;
+							}
+							if (neighbor == -0x7F) {
+								continue;
+							}
+							if (neighbor - kc[ii + jj * 5] > neighbors) {
+								neighbors = neighbor - kc[ii + jj * 5];
+							}
+						}
+					}
+				}
+				if (neighbors == raw) {
+					--left;
+				} else {
+					mImageSetPixelRaw(dst, i, j, neighbors + 0x80);
+				}
+				if (!left) {
+					break;
+				}
+			}
+			if (!left) {
+				break;
+			}
+		}
+		if (!left) {
+			break;
+		}
+	}
+}
+
+int main(int argc, char* argv[]) {
+	struct mImage* source;
+	struct mImage* output;
+
+	if (argc != 3) {
+		return 1;
+	}
+	source = mImageLoad(argv[1]);
+	if (!source) {
+		return 2;
+	}
+	output = mImageCreate(source->width, source->height, mCOLOR_L8);
+	if (!output) {
+		return 3;
+	}
+
+	int i;
+	for (i = 0; i < 128; ++i) {
+		createSdf(source, output, (i & 0xF) << 6, (i & ~0xF) << 2, 64, 64);
+	}
+	for (i = 0; i < GUI_ICON_MAX; ++i) {
+		struct GUIIconMetric metric = defaultIconMetrics[i];
+		metric.width += metric.x & 0xF;
+		metric.height += metric.y & 0xF;
+		metric.x &= ~0xF;
+		metric.y &= ~0xF;
+		createSdf(source, output, metric.x * 4, metric.y * 4 + 512, toPow2(metric.width) * 4, toPow2(metric.height) * 4);
+	}
+	if (!mImageSave(output, argv[2], NULL)) {
+		return 4;
+	}
+	mImageDestroy(source);
+	mImageDestroy(output);
+	return 0;
+}