libsdl-org · ghost · May 10, 2024
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -350,6 +350,8 @@ if(SDL3TTF_SAMPLES)
     add_executable(glfont examples/glfont.c)
     add_executable(showfont examples/showfont.c)
     add_executable(testapp examples/testapp.c)
+    add_executable(AtlasLoadAll examples/AtlasLoadAll.c)
+    #add_executable(Atlas examples/Atlas.cpp)
 
     set(OpenGL_GL_PREFERENCE GLVND)
     find_package(OpenGL)
@@ -361,7 +363,7 @@ if(SDL3TTF_SAMPLES)
         target_link_libraries(glfont PRIVATE OpenGL::GL)
     endif()
 
-    foreach(prog glfont showfont testapp)
+    foreach(prog glfont showfont testapp AtlasLoadAll) #Atlas is cpp so it's not supported?
         sdl_add_warning_options(${prog} WARNING_AS_ERROR ${SDL3TTF_WERROR})
         target_link_libraries(${prog} PRIVATE SDL3_ttf::${sdl3_ttf_target_name})
         target_link_libraries(${prog} PRIVATE ${sdl3_target_name})

diff --git a/examples/Atlas.cpp b/examples/Atlas.cpp
@@ -0,0 +1,191 @@
+#include <SDL3/SDL_render.h>
+#include <SDL3/SDL_surface.h>
+#include <stdio.h>
+#include <SDL3/SDL.h>
+#include "SDL_ttf_atlas.h"
+#include <unordered_map>
+
+SDL_bool useDark, forceDark = 1;
+int renderStyle = 0;
+SDL_Texture*fontTexture;
+SDL_Renderer*renderer;
+std::unordered_map<Uint64, TTF_AtlasEntry*> table; //It's more readable to use TTF_AtlasEntry* than mapping to an index
+
+int spaceXAdv16, baseline16, lineHeight16;
+int spaceXAdv20, baseline20, lineHeight20;
+
+static void DrawWindow(int textureWidth, int textureHeight);
+static void DrawString(const char*text, int x, int y, int spaceXAdv, int baseline, int lineHeight, Uint64 xorID);
+
+static Uint64 AtlasPred(void*user, int glyph) { return glyph ^ (Uint64)user; }
+
+int main(int argc, char *argv[])
+{
+	char buffer[4096];
+	const char*filename=0;
+	for(int i=1; i<argc; i++) {
+		if (argv[i][0] == '-') {
+			//Ignore flags
+		} else {
+			filename = argv[i];
+			break;
+		}
+	}
+#ifdef __WIN32__
+	if (!filename) {
+		#error "TODO"
+		filename="some path.ttf";
+	}
+#else
+	if (!filename) {
+		buffer[0] = 0;
+		FILE*f = popen("fc-match -f %{file}", "r");
+		if (f) {
+			int len = fread(buffer, 1, sizeof(buffer), f);
+			pclose(f);
+			buffer[len] = 0;
+			filename = buffer;
+		}
+	}
+#endif
+
+	TTF_Init();
+
+	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
+		fprintf(stderr, "SDL init failed\n");
+		return 1;
+	}
+
+	useDark = SDL_GetSystemTheme() == SDL_SYSTEM_THEME_DARK;
+	useDark |= forceDark;
+	SDL_Window*window = SDL_CreateWindow("Atlas Test", 1280, 720, SDL_WINDOW_RESIZABLE);
+	if (window == 0) {
+		fprintf(stderr, "SDL_CreateWindow failed\n");
+		return 1;
+	}
+
+	renderer = SDL_CreateRenderer(window, 0, SDL_RENDERER_PRESENTVSYNC);
+
+	TTF_AtlasInfo atlas;
+
+	Uint64 tag16 = 16ULL << 32;
+	Uint64 tag20 = 20ULL << 32;
+	auto atlasState = TTF_AtlasInit(&atlas, 0, 0, 0);
+	//spaceXAdv16 = TTF_AtlasLoadPredicate(filename, 16, atlasState, AtlasPred, (void*)tag16); //This works too
+	spaceXAdv16 = TTF_AtlasLoad(filename, 16, atlasState, 0, 0, 0, tag16); //null range and null list means load everything
+
+	int range20[]={'a', 'z'};
+	//Y is intentionally missing to show we didn't load everything
+	spaceXAdv20 = TTF_AtlasLoad(filename, 20, atlasState, range20, 2, "TE\uFFFD", tag20);
+
+	/*
+	auto pixels = TTF_AtlasDeinitWithPixels(atlasState);
+	SDL_Surface*canvas = SDL_CreateSurfaceFrom(pixels, atlas.width, atlas.height, atlas.width*4, SDL_PIXELFORMAT_ARGB8888);
+	fontTexture = SDL_CreateTextureFromSurface(renderer, canvas);
+	SDL_DestroySurface(canvas); //*/
+
+	/*
+	TTF_AtlasDeinitWithSurface(atlasState);
+	fontTexture = SDL_CreateTextureFromSurface(renderer, atlas.surface); //*/
+
+	fontTexture = TTF_AtlasDeinitWithTexture(atlasState, renderer);
+	if (!fontTexture) {
+		fprintf(stderr, "Failed to create font texture. Error code %d\n", atlas.errorCode);
+		return 1;
+	}
+
+	for(int i = 0; i < atlas.entryLength; i++) {
+		//We should use a hash function since sequential keys are not terrific
+		table.insert({atlas.ids[i], &atlas.entries[i]});
+	}
+
+	//We choose the baseline and line height here
+	//E is a tall common letter, q is a common letter with pixels under the baseline (descent)
+	//Some letters might be taller than E or go further down than q but that's fine
+	//We choose the baseline as the ascent of E plus some padding from the top of the line
+	//Typically the descent is a negative value because it's below the baseline
+	//We choose lineHeight by using baseline (which has padding) subtract the (negative) descent value giving us a larger positive value
+	{
+		baseline16 = table['E' | tag16]->ascent + 2;
+		auto q = table['q' | tag16];
+		lineHeight16 = baseline16 - (q->ascent - q->height);
+
+		baseline20 = table['E' | tag20]->ascent + 2;
+		auto q20 = table['q' | tag20];
+		lineHeight20 = baseline20 - (q20->ascent - q20->height);
+	}
+
+
+	DrawWindow(atlas.width, atlas.height);
+
+	SDL_bool wantQuit = 0;
+	SDL_Event event;
+	while (!wantQuit) {
+		if (!SDL_WaitEvent(&event)) { wantQuit = 1; break; }
+		switch (event.type) {
+			case SDL_EVENT_QUIT: { wantQuit = 1; } break;
+			case SDL_EVENT_KEY_DOWN: {
+				if (event.key.keysym.sym == SDLK_ESCAPE) { wantQuit = 1; break; }
+			} break;
+		}
+		DrawWindow(atlas.width, atlas.height);
+	}
+
+	SDL_DestroyTexture(fontTexture); //Perhaps destory atlas also handle this?
+	TTF_DestroyAtlas(&atlas);
+	TTF_Quit();
+	return 0;
+}
+
+static void DrawWindow(int textureWidth, int textureHeight) {
+	//Choose background and text color of canvas, canvas BG is later
+	if (useDark) {
+		SDL_SetRenderDrawColor(renderer, 0x10, 0x10, 0x10, 255);
+		SDL_SetTextureColorMod(fontTexture, 0xE0, 0xE0, 0xE0);
+	} else {
+		SDL_SetRenderDrawColor(renderer, 0xF0, 0xF0, 0xF0, 255);
+		SDL_SetTextureColorMod(fontTexture, 0x10, 0x10, 0x10);
+	}
+
+	SDL_RenderClear(renderer);
+
+	//Choose canvas background and draw our texture on top
+	SDL_FRect r = {0, 0, textureWidth, textureHeight};
+	if (useDark) SDL_SetRenderDrawColor(renderer, 0, 0, 0x40, 255); else { SDL_SetRenderDrawColor(renderer, 0xC0, 0xC0, 0xFF, 255); }
+	SDL_RenderFillRect(renderer, &r);
+	SDL_RenderTexture(renderer, fontTexture, &r, &r);
+
+	// To test missing characters we replace ~ and ` in our draw function
+	const char *testString = "Test string pq ~ `\nYou may choose the line\nheight however you like\n\nThe quick brown fox\njumped over the lazy dog";
+	DrawString(testString, 1024+4,  20, spaceXAdv16, baseline16, lineHeight16, 16ULL<<32);
+
+	SDL_SetTextureColorMod(fontTexture, 0x40, 0x80, 0x40);
+	DrawString(testString, 1024+4, 240, spaceXAdv20, baseline20, lineHeight20, 20ULL<<32); //Y is intentionally missing to show we didn't load everything
+	SDL_RenderPresent(renderer);
+}
+static void DrawString(const char*text, int x, int y, int spaceXAdv, int baseline, int lineHeight, Uint64 xorID) {
+	if (!text) return;
+	const char*p = text;
+	int startX = x;
+	while (*p) {
+		Sint32 glyph = *p++;
+
+		if (glyph == '~') { glyph = 0x2603; } //2603 is snowman ☃ which is likely missing in the choosen font
+		if (glyph == '`') { glyph = 0xEC08; } //Private font
+
+		if (glyph == ' ') {
+			x += spaceXAdv;
+			continue;
+		} else if (glyph == '\n') {
+			x = startX;
+			y += lineHeight;
+			continue;
+		}
+
+		TTF_AtlasEntry*e = table[ (table.contains(glyph ^ xorID) ? glyph : 0xFFFD) ^ xorID ];
+		SDL_FRect srcRect = {e->canvasX, e->canvasY, e->width, e->height};
+		SDL_FRect dstRect = {x + e->left, y + baseline - e->ascent, e->width, e->height};
+		x += e->xAdv;
+		SDL_RenderTexture(renderer, fontTexture, &srcRect, &dstRect);
+	}
+}
diff --git a/examples/AtlasLoadAll.c b/examples/AtlasLoadAll.c
@@ -0,0 +1,166 @@
+#include <SDL3/SDL_rect.h>
+#include <stdio.h>
+#include <SDL3/SDL.h>
+#include <SDL3_ttf/SDL_ttf.h>
+
+SDL_bool useDark, forceDark = 1;
+TTF_AtlasInfo atlas;
+SDL_Texture*fontTexture;
+SDL_Renderer*renderer;
+int illegalCharIndex, baseline, lineHeight;
+
+void DrawString(const char*text, int x, int y);
+void DrawWindow(void);
+
+int main(int argc, char *argv[])
+{
+	char buffer[4096];
+	const char*filename=0;
+	for(int i=1; i<argc; i++) {
+		if (argv[i][0] == '-') {
+			//Ignore flags
+		} else {
+			filename = argv[i];
+			break;
+		}
+	}
+#ifdef __WIN32__
+	if (!filename) {
+		#error "TODO"
+		filename="some path.ttf";
+	}
+#else
+	if (!filename) {
+		buffer[0] = 0;
+		FILE*f = popen("fc-match -f %{file}", "r");
+		if (f) {
+			int len = fread(buffer, 1, sizeof(buffer), f);
+			pclose(f);
+			buffer[len] = 0;
+			filename = buffer;
+		}
+	}
+#endif
+
+	TTF_Init();
+
+	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
+		fprintf(stderr, "SDL init failed\n");
+		return 1;
+	}
+
+	useDark = SDL_GetSystemTheme() == SDL_SYSTEM_THEME_DARK;
+	useDark |= forceDark;
+	SDL_Window*window = SDL_CreateWindow("Atlas LoadAll Test", 1280, 720, SDL_WINDOW_RESIZABLE);
+	if (window == 0) {
+		fprintf(stderr, "SDL_CreateWindow failed\n");
+		return 1;
+	}
+
+	renderer = SDL_CreateRenderer(window, 0, SDL_RENDERER_PRESENTVSYNC);
+
+	fontTexture = TTF_AtlasLoadAll(filename, 16, renderer, &atlas);
+	if (!fontTexture) {
+		fprintf(stderr, "Failed to create font texture. Error code %d\n", atlas.errorCode);
+		return 1;
+	}
+
+	//We choose the baseline and line height here
+	//E is a tall common letter, q is a common letter with pixels under the baseline (descent)
+	//Some letters might be taller than E or go further down than q but that's fine
+	//We choose the baseline as the ascent of E plus some padding from the top of the line
+	//Typically the descent is a negative value because it's below the baseline
+	//We choose lineHeight by using baseline (which has padding) subtract the (negative) descent value giving us a larger positive value
+	{
+		int foundCount = 0, chosenAscent=0, chosenDescent=0;
+		//The C++ version has a nicer example using a hashtable
+		for(int i=0; i<atlas.entryLength && foundCount < 3; i++) {
+			if (atlas.ids[i] == 'E')
+				chosenAscent = atlas.entries[i].ascent;
+			else if (atlas.ids[i] == 'q') {
+				chosenDescent = atlas.entries[i].ascent - atlas.entries[i].height; //descent is typically a negative value
+			} else if (atlas.ids[i] == 0xFFFD) { // Unicode value of �
+				illegalCharIndex = i;
+				foundCount++;
+			}
+		}
+		baseline = chosenAscent + 2; //Some chars may be taller than 'E' and we would want pixels between lines
+		lineHeight = baseline - chosenDescent; //descent is typically a negative value
+	}
+
+	DrawWindow();
+
+	SDL_bool wantQuit = 0;
+	SDL_Event event;
+	while (!wantQuit) {
+		if (!SDL_WaitEvent(&event)) { wantQuit = 1; break; }
+		switch (event.type) {
+			case SDL_EVENT_QUIT: { wantQuit = 1; } break;
+			case SDL_EVENT_KEY_DOWN: {
+				if (event.key.keysym.sym == SDLK_ESCAPE) { wantQuit = 1; break; }
+			} break;
+		}
+		DrawWindow();
+	}
+
+	SDL_DestroyTexture(fontTexture); //Perhaps destory atlas also handle this?
+	TTF_DestroyAtlas(&atlas);
+	TTF_Quit();
+	return 0;
+}
+
+void DrawWindow(void) {
+	if (useDark) {
+		SDL_SetRenderDrawColor(renderer, 0x10, 0x10, 0x10, 255);
+		SDL_SetTextureColorMod(fontTexture, 0xE0, 0xE0, 0xE0);
+	} else {
+		SDL_SetRenderDrawColor(renderer, 0xF0, 0xF0, 0xF0, 255);
+		SDL_SetTextureColorMod(fontTexture, 0x10, 0x10, 0x10);
+	}
+
+	SDL_RenderClear(renderer);
+
+	SDL_FRect r = {0, 0, atlas.width, atlas.height};
+	if (useDark) SDL_SetRenderDrawColor(renderer, 0, 0, 0x40, 255); else { SDL_SetRenderDrawColor(renderer, 0xC0, 0xC0, 0xFF, 255); }
+	SDL_RenderFillRect(renderer, &r);
+	SDL_RenderTexture(renderer, fontTexture, &r, &r);
+
+	// To test missing characters we replace ~ and ` in our draw function
+	DrawString("Test string pq ~ `\nYou may choose the line\nheight however you like\n\nThe quick brown fox\njumped over the lazy dog", 1024+4, lineHeight);
+	SDL_RenderPresent(renderer);
+}
+
+//The C++ example uses a hashtable
+TTF_AtlasEntry*LookupGlyph(int c) {
+	for(int i=0; i<atlas.entryLength; i++) {
+		if ((int)atlas.ids[i] == c)
+			return  &atlas.entries[i];
+	}
+	return &atlas.entries[illegalCharIndex]; //Usually index of FFFD
+}
+
+void DrawString(const char*text, int x, int y) {
+	if (!text) return;
+	const char*p = text;
+	int startX = x;
+	while (*p) {
+		Sint32 glyph = *p++;
+
+		if (glyph == '~') { glyph = 0x2603; } //2603 is snowman ☃ which is likely missing in the choosen font
+		if (glyph == '`') { glyph = 0xEC08; } //Private font
+
+		if (glyph == ' ') {
+			x += atlas.spaceXAdv;
+			continue;
+		} else if (glyph == '\n') {
+			x = startX;
+			y += lineHeight;
+			continue;
+		}
+		TTF_AtlasEntry*e = LookupGlyph(glyph);
+		SDL_FRect srcRect = {e->canvasX, e->canvasY, e->width, e->height};
+		SDL_FRect dstRect = {x + e->left, y + baseline - e->ascent, e->width, e->height};
+		x += e->xAdv;
+		SDL_RenderTexture(renderer, fontTexture, &srcRect, &dstRect);
+	}
+}