feat: more filters and gpu computed

src/App.vue

@@ -7,6 +7,11 @@ enum Filter {
     Gray = "Gray",
     Sepia = "Sepia",
     Invert = "Invert",
+    Blur = "Blur",
+    Brightness = "Brightness",
+    Contrast = "Contrast",
+    HueShift = "Hue shift",
+    Saturate = "Saturate"
 }
 enum PAPosition {
     None = "None",
@@ -29,6 +34,7 @@ const centerX = ref<number>(0.5);
 const centerY = ref<number>(0.5);
 const zoom = ref<number>(1);
 const filter = ref<Filter>(Filter.None);
+const filterValue = ref<number>(1);
 const paPos = ref<PAPosition>(PAPosition.BR);
 const paScale = ref<number>(0.2);
 const paMargin = ref<number>(0.05);
@@ -65,6 +71,7 @@ function randomize() {
     centerY.value = 0.25 + Math.random() * 0.5;
     zoom.value = 1 + Math.random();
     filter.value = randomElement(Object.values(Filter));
+    filterValue.value = 0.5 + Math.random() * 2;
     paPos.value = randomElement(Object.values(PAPosition));
     paScale.value = 0.1 + Math.random() * 0.2;
     paMargin.value = Math.random() * 0.1;
@@ -76,6 +83,7 @@ function reset() {
     centerY.value = 0.5;
     zoom.value = 1;
     filter.value = Filter.None;
+    filterValue.value = 1;
     paPos.value = PAPosition.BR;
     paScale.value = 0.2;
     paMargin.value = 0.05;
@@ -97,28 +105,6 @@ function download() {
     link.click();
 }
 
-function applyFilter(
-    f: Filter,
-    r: number,
-    g: number,
-    b: number,
-): [number, number, number] {
-    switch (f) {
-        case Filter.Gray:
-            const gray = 0.21 * r + 0.72 * g + 0.07 * b;
-            return [gray, gray, gray];
-        case Filter.Invert:
-            return [255 - r, 255 - g, 255 - b];
-        case Filter.Sepia:
-            return [
-                Math.min(255, Math.round(r * 0.393 + g * 0.769 + b * 0.189)),
-                Math.min(255, Math.round(r * 0.349 + g * 0.686 + b * 0.168)),
-                Math.min(255, Math.round(r * 0.272 + g * 0.534 + b * 0.131)),
-            ];
-    }
-    return [r, g, b];
-}
-
 const drawTimeout = ref<number | undefined>(undefined);
 
 function asyncDraw() {
@@ -144,25 +130,38 @@ function draw(size = PREVIEW_SIZE) {
     const imgHeight = size * (widthFirst ? imgRatio : 1) * zoom.value;
     const dx = (size - imgWidth) * centerX.value;
     const dy = (size - imgHeight) * centerY.value;
+
+    switch(filter.value) {
+        case Filter.Gray:
+            ctx.filter = `grayscale(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+        case Filter.Sepia:
+            ctx.filter = `sepia(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+        case Filter.Invert:
+            ctx.filter = `invert(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+        case Filter.Blur:
+            ctx.filter = `blur(${(filterValue.value * 2 * size / PREVIEW_SIZE).toFixed(2)}px)`
+            break
+        case Filter.Brightness:
+            ctx.filter = `brightness(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+        case Filter.Contrast:
+            ctx.filter = `contrast(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+        case Filter.HueShift:
+            ctx.filter = `hue-rotate(${(filterValue.value * 360).toFixed(2)}deg)`
+            break
+        case Filter.Saturate:
+            ctx.filter = `saturate(${(filterValue.value * 100).toFixed(2)}%)`
+            break
+
+    }
+
     ctx.drawImage(image.value, dx, dy, imgWidth, imgHeight);
 
-    if (filter.value !== Filter.None) {
-        const imageData = ctx.getImageData(0, 0, size, size);
-        const pixelData = imageData.data;
-        for (let i = 0; i < pixelData.length; i += 4) {
-            const r1 = pixelData[i] ?? 0;
-            const g1 = pixelData[i + 1] ?? 0;
-            const b1 = pixelData[i + 2] ?? 0;
-
-            const [r2, g2, b2] = applyFilter(filter.value, r1, g1, b1);
-
-            pixelData[i] = r2;
-            pixelData[i + 1] = g2;
-            pixelData[i + 2] = b2;
-            pixelData[i + 3] = 255;
-        }
-        ctx.putImageData(imageData, 0, 0);
-    }
+    ctx.filter = "none"
 
     if (paPos.value !== PAPosition.None && parentalAdvisory.value) {
         const paWidth = size * paScale.value;
@@ -313,6 +312,21 @@ onMounted(() => {
                         </td>
                         <td></td>
                     </tr>
+                    <tr>
+                        <td><label for="filter-value">Filter Value:</label></td>
+                        <td>
+                            <input
+                                id="filter-value"
+                                v-model="filterValue"
+                                type="range"
+                                min="0"
+                                max="3"
+                                step="0.01"
+                                @input="asyncDraw"
+                            />
+                        </td>
+                        <td>{{ (filterValue * 100).toFixed(0) }}%</td>
+                    </tr>
                     <tr>
                         <td><label for="pa-pos">Sticker Position:</label></td>
                         <td>