From f7ef99a624f2472abb56ec07fc47be5183816c35 Mon Sep 17 00:00:00 2001
From: Alex Turchyn <lexfox777@gmail.com>
Date: Fri, 14 Jul 2023 00:23:15 +0300
Subject: [PATCH] allow to take a photo of signature or type text

---
 .../submission_form/signature_step.vue        | 204 ++++++++++++++++--
 1 file changed, 183 insertions(+), 21 deletions(-)

diff --git a/app/javascript/submission_form/signature_step.vue b/app/javascript/submission_form/signature_step.vue
index 77c12676..50a43341 100644
--- a/app/javascript/submission_form/signature_step.vue
+++ b/app/javascript/submission_form/signature_step.vue
@@ -4,22 +4,52 @@
       <label
         class="label text-2xl"
       >{{ field.name || 'Signature' }}</label>
-      <button
-        v-if="modelValue"
-        class="btn btn-outline btn-sm"
-        @click.prevent="remove"
-      >
-        <IconReload :width="16" />
-        Redraw
-      </button>
-      <button
-        v-else
-        class="btn btn-outline btn-sm"
-        @click.prevent="clear"
-      >
-        <IconReload :width="16" />
-        Clear
-      </button>
+      <div class="space-x-2">
+        <span
+          class="tooltip"
+          data-tip="Type text"
+        >
+          <button
+            class="btn btn-sm btn-circle"
+            :class="{ 'btn-neutral': isTextSignature, 'btn-outline': !isTextSignature }"
+            @click.prevent="toggleTextInput"
+          >
+            <IconTextSize :width="16" />
+          </button>
+        </span>
+        <span
+          class="tooltip"
+          data-tip="Take photo"
+        >
+          <label
+            class="btn btn-outline btn-sm btn-circle"
+          >
+            <IconCamera :width="16" />
+            <input
+              type="file"
+              hidden
+              accept="image/*"
+              @change="drawImage"
+            >
+          </label>
+        </span>
+        <button
+          v-if="modelValue"
+          class="btn btn-outline btn-sm"
+          @click.prevent="remove"
+        >
+          <IconReload :width="16" />
+          Redraw
+        </button>
+        <button
+          v-else
+          class="btn btn-outline btn-sm"
+          @click.prevent="clear"
+        >
+          <IconReload :width="16" />
+          Clear
+        </button>
+      </div>
     </div>
     <input
       :value="modelValue"
@@ -36,16 +66,27 @@
       ref="canvas"
       class="bg-white border border-base-300 rounded"
     />
+    <input
+      v-if="isTextSignature"
+      ref="textInput"
+      class="base-input !text-2xl w-full mt-6"
+      :required="field.required"
+      :placeholder="`Type signature here...`"
+      type="text"
+      @input="updateWrittenSignature"
+    >
   </div>
 </template>
 
 <script>
-import { IconReload } from '@tabler/icons-vue'
+import { IconReload, IconCamera, IconTextSize } from '@tabler/icons-vue'
 
 export default {
   name: 'SignatureStep',
   components: {
-    IconReload
+    IconReload,
+    IconCamera,
+    IconTextSize
   },
   props: {
     field: {
@@ -75,7 +116,8 @@ export default {
   emits: ['attached', 'update:model-value'],
   data () {
     return {
-      isSignatureStarted: false
+      isSignatureStarted: false,
+      isTextSignature: false
     }
   },
   async mounted () {
@@ -104,6 +146,126 @@ export default {
       this.pad.clear()
 
       this.isSignatureStarted = false
+
+      if (this.$refs.textInput) {
+        this.$refs.textInput.value = ''
+      }
+    },
+    updateWrittenSignature (e) {
+      this.isSignatureStarted = true
+
+      const canvas = this.$refs.canvas
+      const context = canvas.getContext('2d')
+
+      const fontFamily = 'Arial'
+      const fontSize = '44px'
+      const fontStyle = 'italic'
+      const fontWeight = ''
+
+      context.font = fontStyle + ' ' + fontWeight + ' ' + fontSize + ' ' + fontFamily
+      context.textAlign = 'center'
+
+      context.clearRect(0, 0, canvas.width, canvas.height)
+      context.fillText(e.target.value, canvas.width / 2, canvas.height / 2 + 11)
+    },
+    toggleTextInput () {
+      this.isTextSignature = !this.isTextSignature
+
+      if (this.isTextSignature) {
+        this.$nextTick(() => this.$refs.textInput.focus())
+      }
+    },
+    drawImage (event) {
+      this.isSignatureStarted = true
+
+      const file = event.target.files[0]
+
+      if (file && file.type.match('image.*')) {
+        const reader = new FileReader()
+
+        reader.onload = (event) => {
+          const img = new Image()
+
+          img.src = event.target.result
+
+          img.onload = () => {
+            const canvas = this.$refs.canvas
+            const context = canvas.getContext('2d')
+
+            const aspectRatio = img.width / img.height
+
+            let targetWidth = canvas.width
+            let targetHeight = canvas.height
+
+            if (canvas.width / canvas.height > aspectRatio) {
+              targetWidth = canvas.height * aspectRatio
+            } else {
+              targetHeight = canvas.width / aspectRatio
+            }
+
+            if (targetHeight > targetWidth) {
+              const scale = targetHeight / targetWidth
+              targetWidth = targetWidth * scale
+              targetHeight = targetHeight * scale
+            }
+
+            const x = (canvas.width - targetWidth) / 2
+            const y = (canvas.height - targetHeight) / 2
+
+            context.clearRect(0, 0, canvas.width, canvas.height)
+            context.drawImage(img, x, y, targetWidth, targetHeight)
+          }
+        }
+
+        reader.readAsDataURL(file)
+      }
+    },
+    cropCanvasAndExportToPNG (canvas) {
+      const ctx = canvas.getContext('2d')
+
+      const width = canvas.width
+      const height = canvas.height
+
+      let topmost = height
+      let bottommost = 0
+      let leftmost = width
+      let rightmost = 0
+
+      const imageData = ctx.getImageData(0, 0, width, height)
+      const pixels = imageData.data
+
+      for (let y = 0; y < height; y++) {
+        for (let x = 0; x < width; x++) {
+          const pixelIndex = (y * width + x) * 4
+          const alpha = pixels[pixelIndex + 3]
+          if (alpha !== 0) {
+            topmost = Math.min(topmost, y)
+            bottommost = Math.max(bottommost, y)
+            leftmost = Math.min(leftmost, x)
+            rightmost = Math.max(rightmost, x)
+          }
+        }
+      }
+
+      const croppedWidth = rightmost - leftmost + 1
+      const croppedHeight = bottommost - topmost + 1
+
+      const croppedCanvas = document.createElement('canvas')
+      croppedCanvas.width = croppedWidth
+      croppedCanvas.height = croppedHeight
+      const croppedCtx = croppedCanvas.getContext('2d')
+
+      croppedCtx.drawImage(canvas, leftmost, topmost, croppedWidth, croppedHeight, 0, 0, croppedWidth, croppedHeight)
+
+      return new Promise((resolve, reject) => {
+        croppedCanvas.toBlob((blob) => {
+          if (blob) {
+            resolve(blob)
+          } else {
+            reject(new Error('Failed to create a PNG blob.'))
+          }
+        }, 'image/png')
+      })
     },
     async submit () {
       if (this.modelValue) {
@@ -111,7 +273,7 @@ export default {
       }
 
       return new Promise((resolve) => {
-        this.$refs.canvas.toBlob(async (blob) => {
+        this.cropCanvasAndExportToPNG(this.$refs.canvas).then(async (blob) => {
           const file = new File([blob], 'signature.png', { type: 'image/png' })
 
           if (this.isDirectUpload) {
@@ -153,7 +315,7 @@ export default {
               return resolve(attachment)
             })
           }
-        }, 'image/png')
+        })
       })
     }
   }