feat: implement page numbers, running titles, and smooth iframe transitions

Add functional page number and running title toggles with proper positioning
for left/right pages. Implement smooth crossfade transitions between iframe
reloads to eliminate visual flicker during PagedJS rendering.

Page Numbers & Running Titles:
- Page numbers toggle: adds counter(page) to @bottom-left (left pages) or
  @bottom-right (right pages)
- Running title toggle: adds string(title) from h2 chapter titles
- Combined positioning: both elements appear side-by-side in same margin box
  - Left pages: "1 Chapter Title" in @bottom-left
  - Right pages: "Chapter Title 2" in @bottom-right
- Automatic CSS rule management: adds/removes @page:left, @page:right, and
  string-set rules based on checkbox state
- Bidirectional sync: checkboxes reflect existing CSS state on load

Smooth Iframe Transitions:
- Dual iframe system: two iframes alternate as visible/hidden
- Crossfade technique: hidden iframe loads new content while visible remains
  displayed, then smooth 300ms opacity transition
- Scroll preservation: saves scroll percentage from visible iframe, restores
  to hidden iframe after PagedJS render
- Collision prevention: isTransitioning flag prevents overlapping renders
- Active frame tracking: computed property ensures ElementPopup always
  references the visible iframe

Technical details:
- Uses srcdoc to inject HTML with dynamic CSS
- Z-index and opacity manipulation for layering
- CSS transitions (opacity 0.3s ease-in-out)
- Automatic frame swapping after transition completes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
isUnknown 2025-12-04 15:27:23 +01:00
parent 9af36fb422
commit 07e5764ccd
2 changed files with 166 additions and 20 deletions

View file

@ -2,23 +2,40 @@
import PagedJsWrapper from './components/PagedJsWrapper.vue';
import EditorPanel from './components/editor/EditorPanel.vue';
import ElementPopup from './components/ElementPopup.vue';
import { onMounted, ref, watch } from 'vue';
import { onMounted, ref, watch, computed } from 'vue';
import { useStylesheetStore } from './stores/stylesheet';
const stylesheetStore = useStylesheetStore();
const previewFrame = ref(null);
const previewFrame1 = ref(null);
const previewFrame2 = ref(null);
const elementPopup = ref(null);
let savedScrollPercentage = 0;
const currentFrameIndex = ref(1); // 1 or 2, which iframe is currently visible
let isTransitioning = false;
const activeFrame = computed(() => {
return currentFrameIndex.value === 1 ? previewFrame1.value : previewFrame2.value;
});
const renderPreview = async (shouldReloadFromFile = false) => {
const iframe = previewFrame.value;
if (!iframe) return;
if (isTransitioning) return;
isTransitioning = true;
if (iframe.contentWindow && iframe.contentDocument) {
const scrollTop = iframe.contentWindow.scrollY || 0;
const scrollHeight = iframe.contentDocument.documentElement.scrollHeight;
const clientHeight = iframe.contentWindow.innerHeight;
// Determine which iframe is currently visible and which to render to
const visibleFrame = currentFrameIndex.value === 1 ? previewFrame1.value : previewFrame2.value;
const hiddenFrame = currentFrameIndex.value === 1 ? previewFrame2.value : previewFrame1.value;
if (!hiddenFrame) {
isTransitioning = false;
return;
}
// Save scroll position from visible frame
if (visibleFrame && visibleFrame.contentWindow && visibleFrame.contentDocument) {
const scrollTop = visibleFrame.contentWindow.scrollY || 0;
const scrollHeight = visibleFrame.contentDocument.documentElement.scrollHeight;
const clientHeight = visibleFrame.contentWindow.innerHeight;
const maxScroll = scrollHeight - clientHeight;
savedScrollPercentage = maxScroll > 0 ? scrollTop / maxScroll : 0;
@ -28,7 +45,8 @@ const renderPreview = async (shouldReloadFromFile = false) => {
await stylesheetStore.loadStylesheet();
}
iframe.srcdoc = `
// Render to the hidden frame
hiddenFrame.srcdoc = `
<!DOCTYPE html>
<html>
<head>
@ -40,20 +58,45 @@ const renderPreview = async (shouldReloadFromFile = false) => {
</html>
`;
iframe.onload = () => {
iframe.contentDocument.addEventListener(
hiddenFrame.onload = () => {
hiddenFrame.contentDocument.addEventListener(
'click',
elementPopup.value.handleIframeClick
);
// Wait for PagedJS to finish rendering
setTimeout(() => {
const scrollHeight = iframe.contentDocument.documentElement.scrollHeight;
const clientHeight = iframe.contentWindow.innerHeight;
// Restore scroll position
const scrollHeight = hiddenFrame.contentDocument.documentElement.scrollHeight;
const clientHeight = hiddenFrame.contentWindow.innerHeight;
const maxScroll = scrollHeight - clientHeight;
const targetScroll = savedScrollPercentage * maxScroll;
iframe.contentWindow.scrollTo(0, targetScroll);
}, 500);
hiddenFrame.contentWindow.scrollTo(0, targetScroll);
// Start crossfade transition
setTimeout(() => {
// Make hidden frame visible (it's already behind)
hiddenFrame.style.opacity = '1';
hiddenFrame.style.zIndex = '1';
// Fade out visible frame
if (visibleFrame) {
visibleFrame.style.opacity = '0';
}
// After fade completes, swap the frames
setTimeout(() => {
if (visibleFrame) {
visibleFrame.style.zIndex = '0';
}
// Swap current frame
currentFrameIndex.value = currentFrameIndex.value === 1 ? 2 : 1;
isTransitioning = false;
}, 300); // Match CSS transition duration
}, 100); // Small delay to ensure scroll is set
}, 500); // Wait for PagedJS
};
};
@ -74,18 +117,30 @@ onMounted(() => renderPreview(true));
<EditorPanel />
<iframe ref="previewFrame" id="preview-frame"></iframe>
<iframe ref="previewFrame1" class="preview-frame"></iframe>
<iframe ref="previewFrame2" class="preview-frame"></iframe>
<ElementPopup ref="elementPopup" :iframeRef="previewFrame" />
<ElementPopup ref="elementPopup" :iframeRef="activeFrame" />
</template>
<style>
#preview-frame {
.preview-frame {
position: fixed;
top: 0;
left: 0;
width: 100vw;
height: 100vh;
border: none;
transition: opacity 0.3s ease-in-out;
}
.preview-frame:nth-of-type(1) {
z-index: 1;
opacity: 1;
}
.preview-frame:nth-of-type(2) {
z-index: 0;
opacity: 0;
}
</style>