Add a new scaleHint to ImageData::load

src/ImageDataWebP.hpp

@@ -1,4 +1,4 @@
-// Copyright 2021 Jan Niklas Hasse <jhasse@bixense.com>
+// Copyright 2021-2024 Jan Niklas Hasse <jhasse@bixense.com>
 // For conditions of distribution and use, see copyright notice in LICENSE.txt
 #pragma once
 
@@ -24,8 +24,8 @@ class ImageDataWebP : public ImageData {
 
 	/// we might scale the image using WebP built-in filter. These functions will return the
 	/// original image size, not the size of the resulting pixel buffer.
-	int getImageWidth() const;
-	int getImageHeight() const;
+	int getImageWidth() const override;
+	int getImageHeight() const override;
 
 private:
 #ifndef __EMSCRIPTEN__

src/jngl/ImageData.cpp

@@ -24,7 +24,7 @@
 
 namespace jngl {
 
-std::unique_ptr<ImageData> ImageData::load(const std::string& filename) {
+std::unique_ptr<ImageData> ImageData::load(const std::string& filename, double scaleHint) {
 	auto fullFilename = pathPrefix + filename;
 	const char* extensions[] = {
 #ifndef NOPNG
@@ -41,8 +41,8 @@ std::unique_ptr<ImageData> ImageData::load(const std::string& filename) {
 		},
 #endif
 #ifndef NOWEBP
-		[](std::string filename, FILE* file) {
-		    return std::make_unique<ImageDataWebP>(std::move(filename), file, 1);
+		[scaleHint](std::string filename, FILE* file) {
+		    return std::make_unique<ImageDataWebP>(std::move(filename), file, scaleHint);
 		},
 #endif
 	};

src/jngl/ImageData.hpp

@@ -15,7 +15,10 @@ class ImageData {
 	/// Passing a filename will load the specified \a filename
 	///
 	/// PNG and WebP files are supported.
-	static std::unique_ptr<ImageData> load(const std::string& filename);
+	///
+	/// \a scaleHint might be completely ignored, compare getImageWidth with getWidth after loading
+	/// to check.
+	static std::unique_ptr<ImageData> load(const std::string& filename, double scaleHint = 1.);
 
 	virtual ~ImageData() = default;
 
@@ -25,22 +28,28 @@ class ImageData {
 	/// Returns the height of the image in pixels
 	virtual int getHeight() const = 0;
 
+	/// If the image has been scaled by getScaleFactor() this will return the original image width
+	virtual int getImageWidth() const = 0;
+	/// If the image has been scaled by getScaleFactor() this will return the original image height
+	virtual int getImageHeight() const = 0;
+
 	/// RGBA values ordered row-major
 	///
 	/// To access the x=5, y=7 pixel's green value:
-	/// `img.pixels()[5 * 4 + 7 * img.getWidth() * 4 + 1]`
+	/// `img->pixels()[5 * 4 + 7 * img->getWidth() * 4 + 1]`
 	///
 	/// This function doesn't create the underlying data or loads the image (that has already
 	/// happened in ImageData::load), so you may call this as often as you like.
 	///
 	/// Example:
 	/// \code
+	/// auto img = ImageData::load("foo");
 	/// size_t x = 5;
 	/// size_t y = 7;
-	/// uint8_t r = img.pixels()[x * 4 + y * img.getWidth() * 4];
-	/// uint8_t g = img.pixels()[x * 4 + y * img.getWidth() * 4 + 1];
-	/// uint8_t b = img.pixels()[x * 4 + y * img.getWidth() * 4 + 2];
-	/// uint8_t a = img.pixels()[x * 4 + y * img.getWidth() * 4 + 3];
+	/// uint8_t r = img->pixels()[x * 4 + y * img->getWidth() * 4];
+	/// uint8_t g = img->pixels()[x * 4 + y * img->getWidth() * 4 + 1];
+	/// uint8_t b = img->pixels()[x * 4 + y * img->getWidth() * 4 + 2];
+	/// uint8_t a = img->pixels()[x * 4 + y * img->getWidth() * 4 + 3];
 	/// \endcode
 	virtual const uint8_t* pixels() const = 0;
 };

src/png/ImageDataPNG.cpp

@@ -1,4 +1,4 @@
-// Copyright 2021 Jan Niklas Hasse <jhasse@bixense.com>
+// Copyright 2021-2024 Jan Niklas Hasse <jhasse@bixense.com>
 // For conditions of distribution and use, see copyright notice in LICENSE.txt
 #include "ImageDataPNG.hpp"
 
@@ -77,4 +77,12 @@ int ImageDataPNG::getHeight() const {
 	return static_cast<int>(y);
 }
 
+int ImageDataPNG::getImageWidth() const {
+	return static_cast<int>(x);
+}
+
+int ImageDataPNG::getImageHeight() const {
+	return static_cast<int>(y);
+}
+
 } // namespace jngl

src/png/ImageDataPNG.hpp

@@ -1,4 +1,4 @@
-// Copyright 2021 Jan Niklas Hasse <jhasse@bixense.com>
+// Copyright 2021-2024 Jan Niklas Hasse <jhasse@bixense.com>
 // For conditions of distribution and use, see copyright notice in LICENSE.txt
 #pragma once
 
@@ -22,6 +22,11 @@ class ImageDataPNG : public ImageData {
     int getWidth() const override;
     int getHeight() const override;
 
+	/// returns getWidth() as PNGs don't support scaling
+	int getImageWidth() const override;
+	/// returns getHeight() as PNGs don't support scaling
+	int getImageHeight() const override;
+
 private:
 	const static unsigned int PNG_BYTES_TO_CHECK = 4;
     std::vector<uint8_t> imageData;