Added ability to supply JSON from standard input

.gitignore

@@ -1,4 +1,13 @@
+# Exclude the executable
 trmnl_sdl
+
+# Exclude configuration files
 *.json
+
+# Exclude images
+*.bmp
+*.jpg
 *.png
+
+# Exclude fonts
 *.ttf

Makefile

@@ -2,8 +2,9 @@ src_files += main.cpp
 src_files += sdl_helpers.cpp
 
 src_files += Widgets/Widget.cpp
-src_files += Widgets/WidgetText.cpp
+src_files += Widgets/WidgetImage.cpp
 src_files += Widgets/WidgetRect.cpp
+src_files += Widgets/WidgetText.cpp
 
 all:
 	g++ $(src_files) -Wall -lSDL2 -lSDL2_ttf -lSDL2_image -o trmnl_sdl

README.md

@@ -9,13 +9,26 @@ You will need the following packages: `build-essential` `libsdl2-dev` `libsdl2-i
 Just run `make` and an executable called `trmnl_sdl` should be produced.
 
 # How to use
-1. You will need to write a JSON config file.
-It can either be named `config.json` or you will need to pass it as the first command line parameter to the executable.
+### General use
+1. You will need to write a JSON config file named `config.json`.
 An example structure of the config file can be found in `config_example.json`.
 You can find more info on the available Widgets and their parameters at the end of this file.
 2. Run the executable
 3. Convert the image to a suitable format via an ImageMagick command from below.
 
+### Different ways to supply JSON
+1. Default
+	* Command: `./trmnl_sdl`
+	* JSON Used: `config.json`
+
+2. Specified file
+	* Command: `./trmnl_sdl path/to/json/file.json`
+	* JSON Used: `path/to/json/file.json`
+
+3. Standard input
+	* Command: `./trmnl_sdl -`
+	* JSON Used: Supplied on the standard input for the process.
+
 # ImageMagick commands to prepare image for TRMNL device
 ### Convert image without dithering
 `convert trmnl.png -monochrome -colors 2 -depth 1 -strip png:output.png`
@@ -63,13 +76,35 @@ Controls vertical alignment of elements. **String** type. Has several options:
 * center - Align objects to be centered
 * bottom - Align objects to the bottom
 
+### ImageResize
+Controls image resizing. **String** type. Has several options:
+* none - Image is not resized and is only clipped by the bounding box
+* fit - Image is uniformly scaled to fit inside the box
+* stretch - Image is scaled (with possible stretching) to fully fill the box
+
 ### TextFit
-Controls automatic change the text size depending on contents. **String** type. Has several options:
+Controls the automatic change of the text size depending on contents. **String** type. Has several options:
 * none - Text is not changed in any way
 * shrink - Renders text with desired size and shrinks it to fit if contents are too large
 * auto - Renders text with desired size and enlarges/shrinks it to fit if contents are too small/large
 
 # List of Widgets and their parameters
+### image
+Renders an image with optional scaling
+| Name | Type | Required | Default | Description |
+| ---: | :--: | :------: | ------: | :---------- |
+| x    | int  |          | 0       | Horizontal position in pixels (from left to right) |
+| y    | int  |          | 0       | Vertical position in pixels (from top to bottom) |
+| width | int | REQ      |         | Width in pixels |
+| height | int | REQ     |         | Height in pixels |
+| filename | string |    |         | Filename of the image to render |
+| resize_type | ImageResize | | fit | Whether to resize the image and how to do so |
+| bg_color | color |     | 255, 255, 255, 0 (Transparent WHITE) | The background color to fill around the image if it is not fully in the box |
+| halign | HAlign |      | center  | Horizontal alignment of the image |
+| valign | VAlign |      | center  | Vertical alignment of the image |
+
+Supported image formats: **JPG**, **PNG**, **BMP**
+
 ### rect
 Renders a rectangle with optional rounded corners using either fill or internal stroke.
 | Name | Type | Required | Default | Description |
@@ -84,7 +119,6 @@ Renders a rectangle with optional rounded corners using either fill or internal
 
 ### text
 Renders text within a specified box
-
 | Name | Type | Required | Default | Description |
 | ---: | :--: | :------: | ------: | :---------- |
 | x    | int  |          | 0       | Horizontal position in pixels (from left to right) |

Widgets/WidgetImage.cpp

@@ -0,0 +1,165 @@
+#include "WidgetImage.h"
+
+#include <SDL2/SDL_image.h>
+
+using std::string;
+
+WidgetImage::WidgetImage(int x, int y, int width, int height, string filename,
+	ImageResize resize_type, HorizontalAlign halign, VerticalAlign valign,
+	SDL_Color bg_color)
+: Widget(x, y, width, height),
+m_filename(filename),
+m_image_surface(nullptr),
+m_resize_type(resize_type),
+m_halign(halign),
+m_valign(valign),
+m_bg_color(bg_color)
+{
+	m_image_surface = IMG_Load(m_filename.c_str());
+	if (nullptr == m_image_surface)
+	{
+		// TODO: Print errors
+	}
+}
+
+void WidgetImage::set_filename(const string& filename)
+{
+	if (m_image_surface != nullptr)
+	{
+		SDL_FreeSurface(m_image_surface);
+		m_image_surface = nullptr;
+	}
+
+	m_filename = filename;
+	m_image_surface = IMG_Load(m_filename.c_str());
+	if (nullptr == m_image_surface)
+	{
+		// TODO: Print errors
+	}
+}
+
+void WidgetImage::set_resize(ImageResize type)
+{
+	m_resize_type = type;
+}
+
+void WidgetImage::set_halign(HorizontalAlign halign)
+{
+	m_halign = halign;
+}
+
+void WidgetImage::set_valign(VerticalAlign valign)
+{
+	m_valign = valign;
+}
+
+void WidgetImage::set_bg_color(SDL_Color bg_color)
+{
+	m_bg_color = bg_color;
+}
+
+
+void WidgetImage::draw()
+{
+	if (nullptr == m_surface)
+	{
+		return;
+	}
+
+	// Clear surface with BG color
+	SDL_FillRect(m_surface, nullptr,
+		SDL_MapRGBA(m_surface->format, m_bg_color.r, m_bg_color.g, m_bg_color.b, m_bg_color.a));
+
+	if (nullptr == m_image_surface)
+	{
+		return;
+	}
+
+	SDL_Rect align;
+	SDL_Surface* scaled_image = nullptr;
+	switch (m_resize_type)
+	{
+	case RESIZE_NONE:
+		align = surface_align(m_surface, m_image_surface, m_halign, m_valign);
+		SDL_BlitSurface(m_image_surface, nullptr, m_surface, &align);
+		break;
+
+	case RESIZE_FIT:
+		scaled_image = image_scale_fit();
+		if (nullptr != scaled_image)
+		{
+			align = surface_align(m_surface, scaled_image, m_halign, m_valign);
+			SDL_BlitScaled(scaled_image, nullptr, m_surface, &align);
+			SDL_FreeSurface(scaled_image);
+		}
+		break;
+
+	case RESIZE_STRETCH:
+		SDL_BlitScaled(m_image_surface, nullptr, m_surface, nullptr);
+		break;
+	}
+}
+
+std::unique_ptr<Widget> WidgetImage::builder(const nlohmann::json& j)
+{
+	int x = 0;
+	int y = 0;
+	int width = 0;
+	int height = 0;
+	string filename;
+	ImageResize resize_type = RESIZE_FIT;
+	HorizontalAlign halign = HALIGN_CENTER;
+	VerticalAlign valign = VALIGN_CENTER;
+	SDL_Color bg_color = {.r = 255, .g = 255, .b = 255, .a = SDL_ALPHA_TRANSPARENT};
+
+	json_extract(j, "x", x);
+	json_extract(j, "y", y);
+	json_extract(j, "width", width);
+	json_extract(j, "height", height);
+	json_extract(j, "filename", filename);
+	json_extract(j, "resize_type", resize_type);
+	json_extract(j, "halign", halign);
+	json_extract(j, "valign", valign);
+	json_extract(j, "bg_color", bg_color);
+
+	return std::make_unique<WidgetImage>(x, y, width, height, filename,
+		resize_type, halign, valign, bg_color);
+}
+
+SDL_Surface* WidgetImage::image_scale_fit()
+{
+	SDL_Rect align = {.x = 0, .y = 0, .w = 0, .h = 0};
+
+	if ((nullptr == m_surface) || (nullptr == m_image_surface))
+	{
+		return nullptr;
+	}
+
+	double x_scale = m_surface->w;
+	x_scale /= m_image_surface->w;
+
+	double y_scale = m_surface->h;
+	y_scale /= m_image_surface->h;
+
+	// Find smallest scale factor
+	double min_scale = x_scale;
+	if (y_scale < min_scale)
+	{
+		min_scale = y_scale;
+	}
+
+	// Scale with double in the front and then clamp to int via SDL_Rect
+	align.w = min_scale * m_image_surface->w;
+	align.h = min_scale * m_image_surface->h;
+
+	SDL_Surface* scaled_image_surface =
+		SDL_CreateRGBSurfaceWithFormat(0, align.w, align.h, 32, SDL_PIXELFORMAT_RGBA8888);
+	if (nullptr == scaled_image_surface)
+	{
+		// TODO: Print Error
+		return nullptr;
+	}
+
+	SDL_BlitScaled(m_image_surface, nullptr, scaled_image_surface, nullptr);
+	return scaled_image_surface;
+}

Widgets/WidgetImage.h

@@ -0,0 +1,59 @@
+#ifndef WIDGET_IMAGE_H_
+#define WIDGET_IMAGE_H_
+
+#include "Widget.h"
+
+#include <string>
+
+#include "../sdl_helpers.h"
+
+// Renders an image with optional scaling
+class WidgetImage : public Widget
+{
+protected:
+	// Image filepath
+	std::string m_filename;
+
+	// Image surface
+	SDL_Surface* m_image_surface;
+
+	// Whether to resize the image and how
+	// RESIZE_NONE - Do not resize
+	// RESIZE_FIT - Scale the image to fit the rectangle
+	// RESIZE_STRETCH - Scale and stretch the image to fit the box perfectly
+	ImageResize m_resize_type;
+
+	// Default - center
+	HorizontalAlign m_halign;
+
+	// Default - center
+	VerticalAlign m_valign;
+
+	// Background color to be used
+	// Default - transparent white
+	SDL_Color m_bg_color;
+
+public:
+	WidgetImage(int x, int y, int width, int height, std::string filename,
+		ImageResize resize_type = RESIZE_FIT,
+		HorizontalAlign halign = HALIGN_CENTER,
+		VerticalAlign valign = VALIGN_CENTER,
+		SDL_Color bg_color = SDL_Color{.r = 255, .g = 255, .b = 255, .a = SDL_ALPHA_TRANSPARENT});
+
+	void set_filename(const std::string& filename);
+	void set_resize(ImageResize type);
+	void set_halign(HorizontalAlign halign);
+	void set_valign(VerticalAlign valign);
+	void set_bg_color(SDL_Color bg_color);
+
+	virtual void draw() override;
+
+	static std::unique_ptr<Widget> builder(const nlohmann::json& j);
+
+protected:
+	// Create a new surface of the image_surface that is scaled via RESIZE_FIT method
+	// NOTE: The user MUST free the surface when done with it
+	SDL_Surface* image_scale_fit();
+};
+
+#endif // WIDGET_IMAGE_H_

Widgets/WidgetRect.cpp

@@ -24,8 +24,28 @@ m_radius(radius)
 {
 }
 
+void WidgetRect::set_color(SDL_Color color)
+{
+	m_color = color;
+}
+
+void WidgetRect::set_stroke_size(int stroke_size)
+{
+	m_stroke_size = stroke_size;
+}
+
+void WidgetRect::set_radius(int radius)
+{
+	m_radius = radius;
+}
+
 void WidgetRect::draw()
 {
+	if (nullptr == m_surface)
+	{
+		return;
+	}
+
 	// Clear surface
 	SDL_FillRect(m_surface, nullptr, SDL_MapRGBA(m_surface->format, 255, 255, 255, SDL_ALPHA_TRANSPARENT));
 

Widgets/WidgetRect.h

@@ -27,11 +27,15 @@ public:
 	WidgetRect(int x, int y, int width, int height,
 		int radius = 0, int stroke_size = -1);
 
+	void set_color(SDL_Color color);
+	void set_stroke_size(int stroke_size);
+	void set_radius(int radius);
+
 	virtual void draw() override;
 
 	static std::unique_ptr<Widget> builder(const nlohmann::json& j);
 
-private:
+protected:
 	// x, y - center of circle
 	// quadrant - 1--4
 	void draw_circle_corner(int x, int y, int quadrant);

Widgets/WidgetText.cpp

@@ -168,8 +168,22 @@ void WidgetText::set_color(SDL_Color text_color)
 	m_text_color = text_color;
 }
 
+void WidgetText::set_halign_via_visible(bool value)
+{
+	m_halign_via_visible = value;
+}
+void WidgetText::set_valign_via_visible(bool value)
+{
+	m_valign_via_visible = value;
+}
+
 void WidgetText::draw()
 {
+	if (nullptr == m_surface)
+	{
+		return;
+	}
+
 	// Clear surface
 	SDL_FillRect(m_surface, nullptr, SDL_MapRGBA(m_surface->format, 255, 255, 255, SDL_ALPHA_TRANSPARENT));
 

Widgets/WidgetText.h

@@ -2,7 +2,6 @@
 #define WIDGET_TEXT_H_
 
 #include "Widget.h"
-#include <SDL2/SDL.h>
 
 #include <string>
 
@@ -71,6 +70,8 @@ public:
 	void set_halign(HorizontalAlign halign);
 	void set_valign(VerticalAlign valign);
 	void set_color(SDL_Color text_color);
+	void set_halign_via_visible(bool value);
+	void set_valign_via_visible(bool value);
 
 	virtual void draw() override;
 

main.cpp

@@ -12,8 +12,9 @@
 
 #include "sdl_helpers.h"
 #include "Widgets/Widget.h"
-#include "Widgets/WidgetText.h"
+#include "Widgets/WidgetImage.h"
 #include "Widgets/WidgetRect.h"
+#include "Widgets/WidgetText.h"
 
 using std::cout;
 using std::endl;
@@ -26,6 +27,7 @@ using nlohmann::json;
 
 void init_builders(map<string, unique_ptr<Widget>(*)(const json&)>& widget_builders)
 {
+	widget_builders["image"] = &WidgetImage::builder;
 	widget_builders["rect"] = &WidgetRect::builder;
 	widget_builders["text"] = &WidgetText::builder;
 }
@@ -58,8 +60,18 @@ int main(int argc, char **argv)
 		cfg_filename = argv[1];
 	}
 
-	// Read JSON CFG
-	ok = read_config_json(cfg, cfg_filename);
+	// Read config
+	if ("-" == cfg_filename)
+	{
+		// Read JSON from std input
+		ok = read_config_json(cfg, std::cin);
+	}
+	else
+	{
+		// Read JSON from config file
+		ok = read_config_json(cfg, cfg_filename);
+	}
+
 	if (!ok)
 	{
 		result = -1;

sdl_helpers.cpp

@@ -87,6 +87,10 @@ SDL_Rect surface_align(const SDL_Surface* base, const SDL_Surface* applied,
 		return align;
 	}
 
+	// These are set in order to handle scaled blits
+	align.w = applied->w;
+	align.h = applied->h;
+
 	if (nullptr == hint_external)
 	{
 		hint = SDL_Rect{.x = 0, .y = 0, .w = applied->w, .h = applied->h};
@@ -137,15 +141,20 @@ bool read_config_json(json& cfg, const string& filename, ostream* log)
 	{
 		if (nullptr != log)
 		{
-			*log << "Could not open config.json" << endl;
+			*log << "Could not open config file" << endl;
 		}
 		return false;
 	}
 
+	return read_config_json(cfg, cfg_file, log);
+}
+
+bool read_config_json(json& cfg, istream& in, ostream* log)
+{
 	// Parse with comments
 	try
 	{
-		cfg = json::parse(cfg_file, nullptr, true, true);
+		cfg = json::parse(in, nullptr, true, true);
 	}
 	catch (const std::exception &e)
 	{
@@ -167,7 +176,7 @@ void json_extract(const json& j, const string& key, string& out)
 	}
 }
 
-void json_extract(const nlohmann::json& j, const string& key, int& out)
+void json_extract(const json& j, const string& key, int& out)
 {
 	if (j.contains(key) && j[key].is_number_integer())
 	{
@@ -175,7 +184,7 @@ void json_extract(const nlohmann::json& j, const string& key, int& out)
 	}
 }
 
-void json_extract(const nlohmann::json& j, const string& key, bool& out)
+void json_extract(const json& j, const string& key, bool& out)
 {
 	if (j.contains(key) && j[key].is_boolean())
 	{
@@ -238,10 +247,24 @@ void json_extract(const json& j, const string& key, SDL_Color& out)
 	}
 }
 
-void json_extract(const nlohmann::json& j, const string& key, Uint8& out)
+void json_extract(const json& j, const string& key, Uint8& out)
 {
 	if (j.contains(key) && j[key].is_number_unsigned())
 	{
 		out = j[key];
 	}
 }
+
+void json_extract(const json& j, const string& key, ImageResize& out)
+{
+	if (j.contains(key))
+	{
+		try
+		{
+			out = j[key].get<ImageResize>();
+		}
+		catch(const std::exception& e)
+		{
+		}
+	}
+}

sdl_helpers.h

@@ -52,6 +52,20 @@ NLOHMANN_JSON_SERIALIZE_ENUM(TextFit,
 	{FIT_AUTO, "auto"},
 })
 
+enum ImageResize
+{
+	RESIZE_NONE,
+	RESIZE_FIT,
+	RESIZE_STRETCH
+};
+
+NLOHMANN_JSON_SERIALIZE_ENUM(ImageResize,
+{
+	{RESIZE_NONE, "none"},
+	{RESIZE_FIT, "fit"},
+	{RESIZE_STRETCH, "stretch"},
+})
+
 // Call this before everything
 // Prints its messages
 bool init_sdl();
@@ -76,6 +90,12 @@ SDL_Rect surface_align(const SDL_Surface* base, const SDL_Surface* applied,
 // log - output errors to this ostream, silent if NULL
 bool read_config_json(nlohmann::json& cfg, const std::string& filename, std::ostream* log = &std::cout);
 
+// Reads the stream and tries to parse JSON from it with comments
+// cfg - output json struct
+// in - input stream to read
+// log - output errors to this ostream, silent if NULL
+bool read_config_json(nlohmann::json& cfg, std::istream& in, std::ostream* log = &std::cout);
+
 // JSON Extractors - They do not override already set values if key is not present
 
 void json_extract(const nlohmann::json& j, const std::string& key, std::string& out);
@@ -86,5 +106,6 @@ void json_extract(const nlohmann::json& j, const std::string& key, VerticalAlign
 void json_extract(const nlohmann::json& j, const std::string& key, TextFit& out);
 void json_extract(const nlohmann::json& j, const std::string& key, SDL_Color& out);
 void json_extract(const nlohmann::json& j, const std::string& key, Uint8& out);
+void json_extract(const nlohmann::json& j, const std::string& key, ImageResize& out);
 
 #endif // SDL_HELPERS_H_