Add qr code support for displays (#2952)

Co-authored-by: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>

esphome/components/qr_code/__init__.py

@@ -0,0 +1,41 @@
+import esphome.config_validation as cv
+import esphome.codegen as cg
+from esphome.const import CONF_ID, CONF_VALUE
+
+CONF_SCALE = "scale"
+CONF_ECC = "ecc"
+
+CODEOWNERS = ["@wjtje"]
+
+DEPENDENCIES = ["display"]
+MULTI_CONF = True
+
+qr_code_ns = cg.esphome_ns.namespace("qr_code")
+QRCode = qr_code_ns.class_("QrCode", cg.Component)
+
+qrcodegen_Ecc = cg.esphome_ns.enum("qrcodegen_Ecc")
+ECC = {
+    "LOW": qrcodegen_Ecc.qrcodegen_Ecc_LOW,
+    "MEDIUM": qrcodegen_Ecc.qrcodegen_Ecc_MEDIUM,
+    "QUARTILE": qrcodegen_Ecc.qrcodegen_Ecc_QUARTILE,
+    "HIGH": qrcodegen_Ecc.qrcodegen_Ecc_HIGH,
+}
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_ID): cv.declare_id(QRCode),
+        cv.Required(CONF_VALUE): cv.string,
+        cv.Optional(CONF_ECC, default="LOW"): cv.enum(ECC, upper=True),
+    }
+)
+
+
+async def to_code(config):
+    cg.add_library("wjtje/qr-code-generator-library", "^1.7.0")
+
+    var = cg.new_Pvariable(config[CONF_ID])
+    cg.add(var.set_value(config[CONF_VALUE]))
+    cg.add(var.set_ecc(ECC[config[CONF_ECC]]))
+    await cg.register_component(var, config)
+
+    cg.add_define("USE_QR_CODE")

esphome/components/qr_code/qr_code.cpp

@@ -0,0 +1,55 @@
+#include "qr_code.h"
+#include "esphome/components/display/display_buffer.h"
+#include "esphome/core/color.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace qr_code {
+
+static const char *const TAG = "qr_code";
+
+void QrCode::dump_config() {
+  ESP_LOGCONFIG(TAG, "QR code:");
+  ESP_LOGCONFIG(TAG, "  Value: '%s'", this->value_.c_str());
+}
+
+void QrCode::set_value(const std::string &value) {
+  this->value_ = value;
+  this->needs_update_ = true;
+}
+
+void QrCode::set_ecc(qrcodegen_Ecc ecc) {
+  this->ecc_ = ecc;
+  this->needs_update_ = true;
+}
+
+void QrCode::generate_qr_code() {
+  ESP_LOGV(TAG, "Generating QR code...");
+  uint8_t tempbuffer[qrcodegen_BUFFER_LEN_MAX];
+
+  if (!qrcodegen_encodeText(this->value_.c_str(), tempbuffer, this->qr_, this->ecc_, qrcodegen_VERSION_MIN,
+                            qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true)) {
+    ESP_LOGE(TAG, "Failed to generate QR code");
+  }
+}
+
+void QrCode::draw(display::DisplayBuffer *buff, uint16_t x_offset, uint16_t y_offset, Color color, int scale) {
+  ESP_LOGV(TAG, "Drawing QR code at (%d, %d)", x_offset, y_offset);
+
+  if (this->needs_update_) {
+    this->generate_qr_code();
+    this->needs_update_ = false;
+  }
+
+  uint8_t qrcode_width = qrcodegen_getSize(this->qr_);
+
+  for (int y = 0; y < qrcode_width * scale; y++) {
+    for (int x = 0; x < qrcode_width * scale; x++) {
+      if (qrcodegen_getModule(this->qr_, x / scale, y / scale)) {
+        buff->draw_pixel_at(x_offset + x, y_offset + y, color);
+      }
+    }
+  }
+}
+}  // namespace qr_code
+}  // namespace esphome

esphome/components/qr_code/qr_code.h

@@ -0,0 +1,34 @@
+#pragma once
+#include "esphome/core/component.h"
+#include "esphome/core/color.h"
+
+#include <cstdint>
+
+#include "qrcodegen.h"
+
+namespace esphome {
+// forward declare DisplayBuffer
+namespace display {
+class DisplayBuffer;
+}  // namespace display
+
+namespace qr_code {
+class QrCode : public Component {
+ public:
+  void draw(display::DisplayBuffer *buff, uint16_t x_offset, uint16_t y_offset, Color color, int scale);
+
+  void dump_config() override;
+
+  void set_value(const std::string &value);
+  void set_ecc(qrcodegen_Ecc ecc);
+
+  void generate_qr_code();
+
+ protected:
+  std::string value_;
+  qrcodegen_Ecc ecc_;
+  bool needs_update_ = true;
+  uint8_t qr_[qrcodegen_BUFFER_LEN_MAX];
+};
+}  // namespace qr_code
+}  // namespace esphome