printing plugin integration

CMakeLists.txt

@@ -35,9 +35,8 @@ option(TRY_BUILD_GSTREAMER_VIDEO_PLAYER_PLUGIN "Don't throw an error if the gstr
 
 option(BUILD_GSTREAMER_AUDIO_PLAYER_PLUGIN "Include the gstreamer based audio plugins in the finished binary." ON)
 option(TRY_BUILD_GSTREAMER_AUDIO_PLAYER_PLUGIN "Don't throw an error if the gstreamer libs aren't found, instead just don't build gstreamer audio plugin." ON)
-
+option(BUILD_PRINTING_PLUGIN "Include the printing plugin in the finished binary." OFF)
 option(BUILD_SENTRY_PLUGIN "Include the sentry plugin in the finished binary. Allows for crash reporting to sentry.io." OFF)
-
 option(BUILD_CHARSET_CONVERTER_PLUGIN "Include the charset converter plugin in the finished binary." OFF)
 option(ENABLE_OPENGL "Build with EGL/OpenGL rendering support." ON)
 option(TRY_ENABLE_OPENGL "Don't throw an error if EGL/OpenGL aren't found, instead just build without EGL/OpenGL support in that case." ON)
@@ -375,6 +374,12 @@ if (BUILD_GSTREAMER_AUDIO_PLAYER_PLUGIN)
   endif()
 endif()
 
+if (BUILD_PRINTING_PLUGIN)
+  pkg_check_modules(IMAGEMAGICK IMPORTED_TARGET MagickWand)
+  target_sources(flutterpi_module PRIVATE src/plugins/printing.c)
+  target_link_libraries(flutterpi_module PUBLIC PkgConfig::IMAGEMAGICK)
+endif()
+
 if (BUILD_CHARSET_CONVERTER_PLUGIN)
   target_sources(flutterpi_module PRIVATE src/plugins/charset_converter.c)
 endif()

README.md

@@ -78,6 +78,11 @@ If you encounter issues running flutter-pi on any of the supported platforms lis
     ```shell
     sudo apt install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libgstreamer-plugins-bad1.0-dev gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly gstreamer1.0-plugins-bad gstreamer1.0-libav gstreamer1.0-alsa
     ```
+
+    If you want to use the [printing](#printing), install these too:
+    ```shell
+    $ sudo apt install imagemagick
+    ```
     <details>
       <summary>More Info</summary>
 
@@ -416,6 +421,13 @@ To use the gstreamer video player, just rebuild flutter-pi (delete your build fo
 
 And then, just use the stuff in the official [video_player](https://pub.dev/packages/video_player) package. (`VideoPlayer`, `VideoPlayerController`, etc, there's nothing specific you need to do on the dart-side)
 
+### printing
+Printing is a plugin that allows Flutter apps to generate and print documents to android or ios compatible printers.
+
+To use the printing plugin, just rebuild flutter-pi (delete your build folder and reconfigure) and make sure the necessary printing packages are installed. (See [dependencies](#dependencies))
+
+And then, just use the stuff in the official [printing](https://pub.dev/packages/printing) package.
+
 ### audioplayers
 As of current moment flutter-pi implements plugin for `audioplayers: ^5.0.0`.
 There are several things you need to keep in mind:
@@ -447,6 +459,7 @@ This is why I created my own (userspace) touchscreen driver, for improved latenc
 | linux_spidev ([package](https://pub.dev/packages/linux_spidev/)) ([repo](https://github.com/ardera/flutter_packages/tree/main/packages/linux_spidev)) | 🖨 peripherals | Hannes Winkler | SPI bus support for dart/flutter, uses kernel interfaces directly for more performance. |
 | dart_periphery ([package](https://pub.dev/packages/dart_periphery)) ([repo](https://github.com/pezi/dart_periphery)) | 🖨 peripherals | [Peter Sauer](https://github.com/pezi/) | All-in-one package GPIO, I2C, SPI, Serial, PWM, Led, MMIO support using c-periphery. |
 | flutterpi_gstreamer_video_player ([package](https://pub.dev/packages/flutterpi_gstreamer_video_player)) ([repo](https://github.com/ardera/flutter_packages/tree/main/packages/flutterpi_gstreamer_video_player)) | ⏯️ multimedia | Hannes Winkler | Official video player implementation for flutter-pi. See [GStreamer video player](#gstreamer-video-player) section above. |
+| printing ([package](https://pub.dev/packages/printing)) ([repo](https://github.com/DavBfr/dart_pdf)) | 🖨 peripherals | David PHAM-VAN | Generate and print documents to android or ios compatible printers. See [printing](#printing) section above. |
 | charset_converter ([package](https://pub.dev/packages/charset_converter)) ([repo](https://github.com/pr0gramista/charset_converter)) | 🗚 encoding | Bartosz Wiśniewski | Encode and decode charsets using platform built-in converter. |
 | sentry_flutter ([package](https://pub.dev/packages/sentry_flutter)) ([repo](https://github.com/getsentry/sentry-dart))|  📊 Monitoring | sentry.io | See https://github.com/ardera/flutter-pi/wiki/Sentry-Support for instructions. |
 

src/plugins/printing.c

@@ -0,0 +1,236 @@
+#include "plugins/printing.h"
+#include "flutter-pi.h"
+#include "pluginregistry.h"
+#include "util/logging.h"
+#include <MagickWand/MagickWand.h>
+
+static void on_page_raster_end(int64_t job, char* error) {
+    struct std_value response = STDMAP1(STDSTRING("job"), STDINT32(job));
+    if (error != NULL) {
+        response = STDMAP2(STDSTRING("job"), STDINT32(job), STDSTRING("error"), STDSTRING(error));
+
+        LOG_ERROR("%s\n", error);
+    }
+
+    platch_call_std(PRINTING_CHANNEL, "onPageRasterEnd", &response, NULL, NULL);
+}
+
+static void on_page_rasterized(int64_t job, const uint8_t* data, size_t size, int width, int height) {
+    struct std_value image = (struct std_value){ .type = kStdUInt8Array, .uint8array  = data, .size = size };
+
+    struct std_value response = STDMAP4(
+        STDSTRING("image"),
+        image,
+        STDSTRING("width"),
+        STDINT32(width),
+        STDSTRING("height"),
+        STDINT32(height),
+        STDSTRING("job"),
+        STDINT32(job)
+    );
+
+    platch_call_std(PRINTING_CHANNEL, "onPageRasterized", &response, NULL, NULL);
+}
+
+static void raster_pdf(const uint8_t *data, size_t size, const int32_t *pages, size_t pages_count, double scale, int64_t job) {
+    MagickWand *wand = NULL;
+    PixelWand *color = NULL;
+
+    int width, height;
+
+    MagickWandGenesis();
+
+    wand = NewMagickWand();
+
+    color = NewPixelWand();
+    PixelSetColor(color, "white");
+
+    MagickBooleanType result = MagickReadImageBlob(wand, data, size);
+    if(result != MagickTrue) {
+        on_page_raster_end(job, "Cannot read images from PDF blob.");
+        return;
+    }
+
+    MagickResetIterator(wand);
+
+    bool all_pages = false;
+    if (pages_count == 0) {
+        all_pages = true;
+        pages_count = MagickGetNumberImages(wand);
+    }
+
+    int current_page = 0;
+    while(MagickNextImage(wand) != MagickFalse) {
+        if(!all_pages){
+            bool shouldRasterize = false;
+
+            //Check if current page is set to be rasterized
+            for(size_t pn = 0; pn < pages_count; pn++) {
+                if(pages[pn] == current_page) {
+                    shouldRasterize = true;
+                    break;
+                }
+            }
+
+            if(!shouldRasterize) {
+                current_page++;
+                continue;
+            }
+        }
+
+        // Get the image's width and height
+        width = MagickGetImageWidth(wand);
+        height = MagickGetImageHeight(wand);
+
+        int32_t bWidth = width * scale;
+        int32_t bHeight = height * scale;
+
+        MagickResizeImage(wand, bWidth, bHeight, LanczosFilter);
+        MagickSetImageFormat(wand, "bmp");
+
+        size_t page_size;
+        uint8_t *page_data = MagickGetImageBlob(wand, &page_size);
+
+        on_page_rasterized(job, page_data, page_size, bWidth, bHeight);
+
+        MagickRelinquishMemory(page_data);
+
+        current_page++;
+    }
+
+    /* Clean up */
+    if(wand){
+        wand = DestroyMagickWand(wand);
+    }
+
+    if(color){
+        color = DestroyPixelWand(color);
+    }
+
+    MagickWandTerminus();
+
+    on_page_raster_end(job, NULL);
+}
+
+static int on_raster_pdf(struct platch_obj *object, FlutterPlatformMessageResponseHandle *response_handle) {
+    struct std_value *args, *tmp;
+    const uint8_t *data;
+    size_t data_length;
+    double scale;
+    int64_t job;
+
+    args = &object->std_arg;
+
+    if (args == NULL || !STDVALUE_IS_MAP(*args)) {
+        return platch_respond_illegal_arg_std(response_handle, "Expected `arg` to be a map.");
+    }
+
+    tmp = stdmap_get_str(&object->std_arg, "doc");
+    if (tmp == NULL || (*tmp).type != kStdUInt8Array ) {
+        return platch_respond_illegal_arg_std(response_handle, "Expected `arg['doc'] to be a uint8_t list.");
+    }
+
+    data = tmp->uint8array;
+    data_length = tmp->size;
+
+    int32_t* pages;
+    size_t pages_count;
+    tmp = stdmap_get_str(&object->std_arg, "pages");
+    if (tmp != NULL || STDVALUE_IS_LIST(*tmp)) {
+        pages_count = tmp->size;
+        pages = (int32_t*)malloc(sizeof(int32_t) * pages_count);
+        for (size_t n = 0; n < pages_count; n++) {
+            struct std_value page = tmp->list[n];
+
+            if(!STDVALUE_IS_INT(page)){
+                continue;
+            }
+
+            pages[n] = page.int32_value;
+        }
+    }
+
+    tmp = stdmap_get_str(&object->std_arg, "scale");
+    if (tmp == NULL || !STDVALUE_IS_FLOAT(*tmp)) {
+        return platch_respond_illegal_arg_std(response_handle, "Expected `arg['scale'] to be a double.");
+    }
+
+    scale = STDVALUE_AS_FLOAT(*tmp);
+
+    tmp = stdmap_get_str(&object->std_arg, "job");
+    if (tmp == NULL || !STDVALUE_IS_INT(*tmp)) {
+        return platch_respond_illegal_arg_std(response_handle, "Expected `arg['job'] to be an int.");
+    }
+
+    job = STDVALUE_AS_INT(*tmp);
+
+    //Rasterize
+    raster_pdf(data, data_length, pages, pages_count, scale, job);
+
+    free(pages);
+
+    return platch_respond(
+        response_handle,
+        &(struct platch_obj){ .codec = kStandardMethodCallResponse, .success = true, .std_result = { .type = kStdTrue } }
+    );
+}
+
+static int on_printing_info(struct platch_obj *object, FlutterPlatformMessageResponseHandle *response_handle) {  
+    (void) object;
+
+    return platch_respond(
+        response_handle,
+        &PLATCH_OBJ_STD_MSG(STDMAP6(
+            STDSTRING("canPrint"),
+            STDBOOL(false),
+            STDSTRING("canShare"),
+            STDBOOL(false),
+            STDSTRING("canRaster"),
+            STDBOOL(true),
+            STDSTRING("canListPrinters"),
+            STDBOOL(false),
+            STDSTRING("directPrint"),
+            STDBOOL(false),
+            STDSTRING("dynamicLayout"),
+            STDBOOL(false)
+        ))
+    );
+}
+
+static int on_receive(char *channel, struct platch_obj *object, FlutterPlatformMessageResponseHandle *response_handle) {
+    (void) channel;
+
+    const char *method;
+    method = object->method;
+
+    if (streq(method, "printingInfo")) {
+        return on_printing_info(object, response_handle);
+    } else if (streq(method, "rasterPdf")) {
+        return on_raster_pdf(object, response_handle);
+    }
+
+    return platch_respond_not_implemented(response_handle);
+}
+
+enum plugin_init_result printing_init(struct flutterpi *flutterpi, void **userdata_out) {
+    (void) flutterpi;
+
+    int ok;
+
+    ok = plugin_registry_set_receiver_locked(PRINTING_CHANNEL, kStandardMethodCall, on_receive);
+    if (ok != 0) {
+        return PLUGIN_INIT_RESULT_ERROR;
+    }
+
+    *userdata_out = NULL;
+
+    return PLUGIN_INIT_RESULT_INITIALIZED;
+}
+
+void printing_deinit(struct flutterpi *flutterpi, void *userdata) {
+    (void) userdata;
+
+    plugin_registry_remove_receiver_v2_locked(flutterpi_get_plugin_registry(flutterpi), PRINTING_CHANNEL);
+}
+
+FLUTTERPI_PLUGIN("printing plugin", printing_plugin, printing_init, printing_deinit)

src/plugins/printing.h

@@ -0,0 +1,9 @@
+#ifndef _PRINTING_PLUGIN_H
+#define _PRINTING_PLUGIN_H
+
+#include <stdio.h>
+#include <string.h>
+
+#define PRINTING_CHANNEL "net.nfet.printing"
+
+#endif