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

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

@@ -22,6 +22,43 @@ m_bg_color(bg_color)
 	}
 }
 
+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)

Widgets/WidgetImage.h

@@ -7,6 +7,7 @@
 
 #include "../sdl_helpers.h"
 
+// Renders an image with optional scaling
 class WidgetImage : public Widget
 {
 protected:
@@ -39,6 +40,12 @@ public:
 		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);

Widgets/WidgetRect.cpp

@@ -24,6 +24,21 @@ 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)

Widgets/WidgetRect.h

@@ -27,6 +27,10 @@ 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);

Widgets/WidgetText.cpp

@@ -168,6 +168,15 @@ 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)

Widgets/WidgetText.h

@@ -70,6 +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

@@ -60,8 +60,18 @@ int main(int argc, char **argv)
 		cfg_filename = argv[1];
 	}
 
-	// Read JSON CFG
+	// 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

@@ -141,15 +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)
 	{

sdl_helpers.h

@@ -90,6 +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);