[runtime_image, online_image] Create runtime_image component to decode images (#10212)

esphome/components/runtime_image/image_decoder.cpp

@@ -0,0 +1,28 @@
+#include "image_decoder.h"
+#include "runtime_image.h"
+#include "esphome/core/log.h"
+#include <algorithm>
+#include <cmath>
+
+namespace esphome::runtime_image {
+
+static const char *const TAG = "image_decoder";
+
+bool ImageDecoder::set_size(int width, int height) {
+  bool success = this->image_->resize(width, height) > 0;
+  this->x_scale_ = static_cast<double>(this->image_->get_buffer_width()) / width;
+  this->y_scale_ = static_cast<double>(this->image_->get_buffer_height()) / height;
+  return success;
+}
+
+void ImageDecoder::draw(int x, int y, int w, int h, const Color &color) {
+  auto width = std::min(this->image_->get_buffer_width(), static_cast<int>(std::ceil((x + w) * this->x_scale_)));
+  auto height = std::min(this->image_->get_buffer_height(), static_cast<int>(std::ceil((y + h) * this->y_scale_)));
+  for (int i = x * this->x_scale_; i < width; i++) {
+    for (int j = y * this->y_scale_; j < height; j++) {
+      this->image_->draw_pixel(i, j, color);
+    }
+  }
+}
+
+}  // namespace esphome::runtime_image