Implement warning diagnostic flags for RGBGFX (#1738)

src/gfx/main.cpp

@@ -52,7 +52,7 @@ void Options::verbosePrint(uint8_t level, char const *fmt, ...) const {
 }
 
 // Short options
-static char const *optstring = "-Aa:B:b:Cc:d:hi:L:l:mN:n:Oo:Pp:Qq:r:s:Tt:U:uVvXx:YZ";
+static char const *optstring = "-Aa:B:b:Cc:d:hi:L:l:mN:n:Oo:Pp:Qq:r:s:Tt:U:uVvW:wXx:YZ";
 
 // Equivalent long options
 // Please keep in the same order as short opts.
@@ -90,6 +90,7 @@ static option const longopts[] = {
     {"unique-tiles",     no_argument,       nullptr, 'u'},
     {"version",          no_argument,       nullptr, 'V'},
     {"verbose",          no_argument,       nullptr, 'v'},
+    {"warning",          required_argument, nullptr, 'W'},
     {"mirror-x",         no_argument,       nullptr, 'X'},
     {"trim-end",         required_argument, nullptr, 'x'},
     {"mirror-y",         no_argument,       nullptr, 'Y'},
@@ -558,6 +559,12 @@ static char *parseArgv(int argc, char *argv[]) {
 			}
 			break;
 			// LCOV_EXCL_STOP
+		case 'W':
+			warnings.processWarningFlag(musl_optarg);
+			break;
+		case 'w':
+			warnings.state.warningsEnabled = false;
+			break;
 		case 'x':
 			options.trim = parseNumber(arg, "Number of tiles to trim", 0);
 			if (*arg != '\0') {

src/gfx/process.cpp

@@ -615,6 +615,10 @@ static std::tuple<std::vector<size_t>, std::vector<Palette>>
 		sortGrayscale(palettes, png.getColors().raw());
 	} else if (auto [embPalSize, embPalRGB, embPalAlphaSize, embPalAlpha] = png.getEmbeddedPal();
 	           embPalRGB != nullptr) {
+		warning(
+		    WARNING_EMBEDDED,
+		    "Sorting palette colors by PNG's embedded PLTE chunk without '-c/--colors embedded'"
+		);
 		sortIndexed(palettes, embPalSize, embPalRGB, embPalAlphaSize, embPalAlpha);
 	} else if (png.isSuitableForGrayscale()) {
 		sortGrayscale(palettes, png.getColors().raw());
@@ -870,32 +874,41 @@ static void outputUnoptimizedTileData(
 	uint16_t widthTiles = options.inputSlice.width ? options.inputSlice.width : png.getWidth() / 8;
 	uint16_t heightTiles =
 	    options.inputSlice.height ? options.inputSlice.height : png.getHeight() / 8;
-	uint64_t remainingTiles = widthTiles * heightTiles;
-	if (remainingTiles <= options.trim) {
-		return;
-	}
-	remainingTiles -= options.trim;
+	uint64_t nbTiles = widthTiles * heightTiles;
+	uint64_t nbKeptTiles = nbTiles > options.trim ? nbTiles - options.trim : 0;
+	uint64_t tileIdx = 0;
 
 	for (auto [tile, attr] : zip(png.visitAsTiles(), attrmap)) {
 		// Do not emit fully-background tiles.
 		if (!attr.isBackgroundTile()) {
 			// If the tile is fully transparent, this defaults to palette 0.
 			Palette const &palette = palettes[attr.getPalID(mappings)];
+
+			bool empty = true;
 			for (uint32_t y = 0; y < 8; ++y) {
 				uint16_t bitplanes = TileData::rowBitplanes(tile, palette, y);
-				output->sputc(bitplanes & 0xFF);
-				if (options.bitDepth == 2) {
-					output->sputc(bitplanes >> 8);
+				if (bitplanes != 0) {
+					empty = false;
+				}
+				if (tileIdx < nbKeptTiles) {
+					output->sputc(bitplanes & 0xFF);
+					if (options.bitDepth == 2) {
+						output->sputc(bitplanes >> 8);
+					}
 				}
 			}
-		}
 
-		--remainingTiles;
-		if (remainingTiles == 0) {
-			break;
+			if (!empty && tileIdx >= nbKeptTiles) {
+				warning(
+				    WARNING_TRIM_NONEMPTY,
+				    "Trimming a nonempty tile (configure with '-x/--trim-end'"
+				);
+				break; // Don't repeat the warning for subsequent tiles
+			}
 		}
+		++tileIdx;
 	}
-	assume(remainingTiles == 0);
+	assume(nbKeptTiles <= tileIdx && tileIdx <= nbTiles);
 }
 
 static void outputUnoptimizedMaps(

src/gfx/warning.cpp

@@ -10,6 +10,21 @@
 
 static uintmax_t nbErrors;
 
+// clang-format off: nested initializers
+Diagnostics<WarningLevel, WarningID> warnings = {
+    .metaWarnings = {
+        {"all",           LEVEL_ALL       },
+        {"everything",    LEVEL_EVERYTHING},
+    },
+    .warningFlags = {
+        {"embedded",      LEVEL_EVERYTHING},
+        {"trim-nonempty", LEVEL_ALL       },
+    },
+    .paramWarnings = {},
+    .state = DiagnosticsState<WarningID>(),
+};
+// clang-format on
+
 [[noreturn]]
 void giveUp() {
 	fprintf(stderr, "Conversion aborted after %ju error%s\n", nbErrors, nbErrors == 1 ? "" : "s");
@@ -50,3 +65,33 @@ void fatal(char const *fmt, ...) {
 
 	giveUp();
 }
+
+void warning(WarningID id, char const *fmt, ...) {
+	char const *flag = warnings.warningFlags[id].name;
+	va_list ap;
+
+	switch (warnings.getWarningBehavior(id)) {
+	case WarningBehavior::DISABLED:
+		break;
+
+	case WarningBehavior::ENABLED:
+		fprintf(stderr, "warning: [-W%s]\n    ", flag);
+		va_start(ap, fmt);
+		vfprintf(stderr, fmt, ap);
+		va_end(ap);
+		putc('\n', stderr);
+		break;
+
+	case WarningBehavior::ERROR:
+		fprintf(stderr, "error: [-Werror=%s]\n    ", flag);
+		va_start(ap, fmt);
+		vfprintf(stderr, fmt, ap);
+		va_end(ap);
+		putc('\n', stderr);
+
+		if (nbErrors != std::numeric_limits<decltype(nbErrors)>::max()) {
+			nbErrors++;
+		}
+		break;
+	}
+}