Factorization of image rotation

Refs: #16

.clang-format-ignore

@@ -1,3 +1,2 @@
 src/about.cc
-src/icons.cc
 src/l10n.cc

src/hourlyforecastbox.cc

@@ -466,39 +466,12 @@ void HourlyForecastBox::draw_sunrise_sunset_lines() const {
 std::map<int, std::vector<unsigned char>> rotated_icons;
 
 const ibitmap *HourlyForecastBox::rotate_direction_icon(int degree) {
-  const auto arrow_angle = (180 - degree);
-  // The parameter degree is an angle measure in degrees, interpreted
-  // as the direction where the wind is blowing FROM (0 means North,
-  // 90 East), but the icon arrow must show where the wind is blowing
-  // TO. Whats more OpenCV rotation is counter-clockwise for positive
-  // angle values.
   auto found = rotated_icons.find(degree);
   if (found == rotated_icons.end()) {
-    auto *const icon_to_rotate = const_cast<ibitmap *>(this->direction_icon);
-    const cv::Mat image{icon_to_rotate->height, icon_to_rotate->width, CV_8UC1,
-                        icon_to_rotate->data};
-    const cv::Point2f center{
-        static_cast<float>((icon_to_rotate->width - 1) / 2.0),
-        static_cast<float>((icon_to_rotate->height - 1) / 2.0)};
-    const cv::Mat rotation_matrix =
-        cv::getRotationMatrix2D(center, arrow_angle, 1.0);
-    cv::Mat rotated_image{icon_to_rotate->height, icon_to_rotate->width,
-                          CV_8UC1};
-    cv::warpAffine(image, rotated_image, rotation_matrix, image.size(),
-                   cv::INTER_LINEAR, cv::BORDER_CONSTANT, 0xFF);
-
-    const auto header_size = offsetof(ibitmap, data);
-    const auto data_size = icon_to_rotate->scanline * icon_to_rotate->height;
-    auto &rotated_bitmap_data = rotated_icons[degree];
-    rotated_bitmap_data.resize(header_size + data_size);
-
-    std::memcpy(rotated_bitmap_data.data(), icon_to_rotate, header_size);
-    // headers are the same for both bitmap
-
-    std::memcpy(rotated_bitmap_data.data() + header_size, rotated_image.data,
-                data_size);
-
-    return reinterpret_cast<ibitmap *>(rotated_bitmap_data.data());
+
+    rotated_icons[degree] = this->icons->rotate_icon(
+        const_cast<ibitmap *>(this->direction_icon), degree);
+    return reinterpret_cast<ibitmap *>(rotated_icons[degree].data());
   }
   return reinterpret_cast<ibitmap *>(found->second.data());
 }

src/hourlyforecastbox.h

@@ -52,8 +52,6 @@ class HourlyForecastBox : public Widget, public Paginated {
   std::shared_ptr<Icons> icons;
   std::shared_ptr<Fonts> fonts;
 
-  std::map<int, const ibitmap *> rotated_direction_icons;
-
   const ibitmap *const direction_icon;
 
   int bar_width;

src/icons.cc

@@ -0,0 +1,46 @@
+#include "icons.h"
+
+#include <cstring>
+#include <opencv2/imgproc.hpp>
+#include <opencv2/imgproc/imgproc.hpp>
+#include <opencv2/opencv.hpp>
+
+namespace taranis {
+
+std::vector<unsigned char> Icons::rotate_icon(ibitmap *icon_to_rotate,
+                                              int degree) {
+  const auto arrow_angle = (180 - degree);
+  // The parameter degree is an angle measure in degrees, interpreted
+  // as the direction where the wind is blowing FROM (0 means North,
+  // 90 East), but the icon arrow must show where the wind is blowing
+  // TO. Whats more OpenCV rotation is counter-clockwise for positive
+  // angle values.
+  if (!icon_to_rotate) {
+    return {};
+  }
+  const cv::Mat image{icon_to_rotate->height, icon_to_rotate->width, CV_8UC1,
+                      icon_to_rotate->data};
+  const cv::Point2f center{
+      static_cast<float>((icon_to_rotate->width - 1) / 2.0),
+      static_cast<float>((icon_to_rotate->height - 1) / 2.0)};
+  const cv::Mat rotation_matrix =
+      cv::getRotationMatrix2D(center, arrow_angle, 1.0);
+  cv::Mat rotated_image{icon_to_rotate->height, icon_to_rotate->width, CV_8UC1};
+  cv::warpAffine(image, rotated_image, rotation_matrix, image.size(),
+                 cv::INTER_LINEAR, cv::BORDER_CONSTANT, 0xFF);
+
+  const auto header_size = offsetof(ibitmap, data);
+  const auto data_size = icon_to_rotate->scanline * icon_to_rotate->height;
+
+  std::vector<unsigned char> rotated_bitmap_data;
+  rotated_bitmap_data.resize(header_size + data_size);
+
+  std::memcpy(rotated_bitmap_data.data(), icon_to_rotate, header_size);
+  // headers are the same for both bitmap
+
+  std::memcpy(rotated_bitmap_data.data() + header_size, rotated_image.data,
+              data_size);
+
+  return rotated_bitmap_data;
+}
+} // namespace taranis

src/icons.h

@@ -1,8 +1,10 @@
 #pragma once
 
 #include <boost/log/trivial.hpp>
-#include <inkview.h>
 #include <string>
+#include <vector>
+
+#include <inkview.h>
 
 extern const ibitmap icon_01n_2x;
 extern const ibitmap icon_02n_2x;
@@ -102,5 +104,7 @@ class Icons {
 
     return nullptr;
   }
+
+  std::vector<unsigned char> rotate_icon(ibitmap *icon_to_rotate, int degree);
 };
 } // namespace taranis

src/meson.build

@@ -27,21 +27,21 @@ pbres_command = find_program(
 sed_command = find_program('sed', required: true)
 # dependency of convert_resources_command
 
-icons_c = custom_target(
+icons_resources_c = custom_target(
   'generate-icons-resources-c',
-  output: 'icons.c',
+  output: 'icon_resources.c',
   input: icons,
   command: [pbres_command, '-c', '@OUTPUT@', '-8', '@INPUT@']
 )
 
 convert_resources_command = find_program('../scripts/convert_ressources.sh',
                                          required: true)
 
-icons_cc = custom_target(
+icon_resources_cc = custom_target(
   'convert-resources-cc',
-  output: 'icons.cc',
-  input: icons_c,
-  depends: [icons_c],
+  output: 'icon_resources.cc',
+  input: icons_resources_c,
+  depends: [icons_resources_c],
   command: [convert_resources_command, '@INPUT@', '@OUTPUT@']
 )
 
@@ -59,7 +59,7 @@ l10n_cc = custom_target(
             '@SOURCE_ROOT@/po']
 )
 
-sources = [about_cc, icons_cc, l10n_cc] + files(
+sources = [about_cc, icon_resources_cc, l10n_cc] + files(
   'alerts.cc',
   'app.cc',
   'config.cc',
@@ -71,6 +71,7 @@ sources = [about_cc, icons_cc, l10n_cc] + files(
   'forecast.cc',
   'hourlyforecastbox.cc',
   'http.cc',
+  'icons.cc',
   'locationbox.cc',
   'locationselector.cc',
   'logging.cc',