C++

C++ example for image generation using the Canvasflare API.

The Canvasflare API provides the functionality to create images from HTML, CSS, and additional rendering options. This example illustrates how to make a POST request to generate an image using C++.

Rendering an Image

Send a POST request to https://api.canvasflare.com/render?api_key=YOUR_API_KEY with the required parameters.

Parameters

• html - The HTML content you wish to render, e.g., <div>Your content</div>.
• css - The CSS styling for your rendered image, e.g., .h1 { color: red }.
• device_scale - Modifies the pixel density of the screenshot.
• viewport_width - The width of the Chrome viewport.
• viewport_height - The height of the Chrome viewport.
• viewport_device - Emulates a given device's metrics and user agent.
• viewport_has_touch - Indicates whether the viewport supports touch events.
• viewport_landscape - Indicates whether the viewport is in landscape mode.
• viewport_mobile - Specifies whether the meta viewport tag is considered.
• full_page - If set to true screenshots entire webpage.
• selector - A CSS selector corresponding to an element in the HTML.
• ms_delay - Additional delay to ensure completion of JavaScript execution.
• user_agent - An user agent for the request.

Example Request in C++

You can use libraries like libcurl (for HTTP requests) and nlohmann/json (for JSON handling) in C++:

#include <curl/curl.h>
#include <nlohmann/json.hpp>
#include <iostream>
#include <string>

using json = nlohmann::json;

static size_t WriteCallback(void *contents, size_t size, size_t nmemb, std::string *s) {
    size_t newLength = size * nmemb;
    try {
        s->append((char*)contents, newLength);
        return newLength;
    } catch(std::bad_alloc &e) {
        // handle memory problem
        return 0;
    }
}

int main() {
    curl_global_init(CURL_GLOBAL_ALL);
    CURL *curl = curl_easy_init();
    if(curl) {
        const std::string url = "https://api.canvasflare.com/render?api_key=YOUR_API_KEY";

        json j;
        j["html"] = "<div>This is something</div>";
        j["css"] = ".h1 { color: red }";
        j["device_scale"] = 2;
        j["viewport_width"] = 640;
        j["viewport_height"] = 480;
        j["ms_delay"] = 500;

        std::string readBuffer;
        struct curl_slist *headers = NULL;
        headers = curl_slist_append(headers, "Content-Type: application/json");

    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
        curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS, j.dump().c_str());
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);

        CURLcode res = curl_easy_perform(curl);
        if(res != CURLE_OK) {
            fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
        } else {
            std::cout << readBuffer << std::endl; // Output response
        }

        curl_slist_free_all(headers);
        curl_easy_cleanup(curl);
    }
    curl_global_cleanup();
    return 0;
}

Response

The API response will return a URL to the generated image that you can download or display.

Make Your Image URL Downloadable

You can add the parameter ?dl=true to the image URL to make the browser download the image automatically. For example:

https://api.canvasflare.com/image/8d063c49-3f15-46c1-91c7-9cf61e6758c6?dl=true

Dependency

To run this C++ code, you will need to have libcurl for making HTTP requests and nlohmann/json for JSON handling. Make sure these libraries are installed and properly set up in your C++ project environment. The code is a basic example and might require additional error handling or adjustments based on your specific requirements and setup.