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Use double buffering for the display

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Do all rendering to a hidden canvas and then copy over the finished
frame to the visible canvas once everything is done. This simplifies
things and solves some bugs as we can retain a copy of the entire
frame buffer.
This commit is contained in:
Pierre Ossman
2016-10-25 16:58:21 +02:00
parent 18d21e3621
commit 2ba767a7fe
4 changed files with 143 additions and 287 deletions
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263
core/display.js
View File

@@ -32,7 +32,6 @@
// the visible "physical canvas" viewport
this._viewportLoc = { 'x': 0, 'y': 0, 'w': 0, 'h': 0 };
this._cleanRect = { 'x1': 0, 'y1': 0, 'x2': -1, 'y2': -1 };
this._prevDrawStyle = "";
this._tile = null;
@@ -51,6 +50,7 @@
Util.Debug(">> Display.constructor");
// The visible canvas
if (!this._target) {
throw new Error("Target must be set");
}
@@ -63,9 +63,11 @@
throw new Error("no getContext method");
}
if (!this._drawCtx) {
this._drawCtx = this._target.getContext('2d');
}
this._targetCtx = this._target.getContext('2d');
// The hidden canvas, where we do the actual rendering
this._backbuffer = document.createElement('canvas');
this._drawCtx = this._backbuffer.getContext('2d');
Util.Debug("User Agent: " + navigator.userAgent);
if (Util.Engine.gecko) { Util.Debug("Browser: gecko " + Util.Engine.gecko); }
@@ -145,78 +147,9 @@
Util.Debug("viewportChange deltaX: " + deltaX + ", deltaY: " + deltaY);
vp.x += deltaX;
vx2 += deltaX;
vp.y += deltaY;
vy2 += deltaY;
// Update the clean rectangle
var cr = this._cleanRect;
if (vp.x > cr.x1) {
cr.x1 = vp.x;
}
if (vx2 < cr.x2) {
cr.x2 = vx2;
}
if (vp.y > cr.y1) {
cr.y1 = vp.y;
}
if (vy2 < cr.y2) {
cr.y2 = vy2;
}
var x1, w;
if (deltaX < 0) {
// Shift viewport left, redraw left section
x1 = 0;
w = -deltaX;
} else {
// Shift viewport right, redraw right section
x1 = vp.w - deltaX;
w = deltaX;
}
var y1, h;
if (deltaY < 0) {
// Shift viewport up, redraw top section
y1 = 0;
h = -deltaY;
} else {
// Shift viewport down, redraw bottom section
y1 = vp.h - deltaY;
h = deltaY;
}
var saveStyle = this._drawCtx.fillStyle;
var canvas = this._target;
this._drawCtx.fillStyle = "rgb(255,255,255)";
// Due to this bug among others [1] we need to disable the image-smoothing to
// avoid getting a blur effect when panning.
//
// 1. https://bugzilla.mozilla.org/show_bug.cgi?id=1194719
//
// We need to set these every time since all properties are reset
// when the the size is changed
if (this._drawCtx.mozImageSmoothingEnabled) {
this._drawCtx.mozImageSmoothingEnabled = false;
} else if (this._drawCtx.webkitImageSmoothingEnabled) {
this._drawCtx.webkitImageSmoothingEnabled = false;
} else if (this._drawCtx.msImageSmoothingEnabled) {
this._drawCtx.msImageSmoothingEnabled = false;
} else if (this._drawCtx.imageSmoothingEnabled) {
this._drawCtx.imageSmoothingEnabled = false;
}
// Copy the valid part of the viewport to the shifted location
this._drawCtx.drawImage(canvas, 0, 0, vp.w, vp.h, -deltaX, -deltaY, vp.w, vp.h);
if (deltaX !== 0) {
this._drawCtx.fillRect(x1, 0, w, vp.h);
}
if (deltaY !== 0) {
this._drawCtx.fillRect(0, y1, vp.w, h);
}
this._drawCtx.fillStyle = saveStyle;
this.flip();
},
viewportChangeSize: function(width, height) {
@@ -240,29 +173,11 @@
}
}
var cr = this._cleanRect;
if (width < vp.w && cr.x2 > vp.x + width - 1) {
cr.x2 = vp.x + width - 1;
}
if (height < vp.h && cr.y2 > vp.y + height - 1) {
cr.y2 = vp.y + height - 1;
}
vp.w = width;
vp.h = height;
var canvas = this._target;
if (canvas.width !== width || canvas.height !== height) {
// We have to save the canvas data since changing the size will clear it
var saveImg = null;
if (vp.w > 0 && vp.h > 0 && canvas.width > 0 && canvas.height > 0) {
var img_width = canvas.width < vp.w ? canvas.width : vp.w;
var img_height = canvas.height < vp.h ? canvas.height : vp.h;
saveImg = this._drawCtx.getImageData(0, 0, img_width, img_height);
}
if (canvas.width !== width) {
canvas.width = width;
canvas.style.width = width + 'px';
@@ -271,63 +186,11 @@
canvas.height = height;
canvas.style.height = height + 'px';
}
if (saveImg) {
this._drawCtx.putImageData(saveImg, 0, 0);
}
this.flip();
}
}
},
// Return a map of clean and dirty areas of the viewport and reset the
// tracking of clean and dirty areas
//
// Returns: { 'cleanBox': { 'x': x, 'y': y, 'w': w, 'h': h},
// 'dirtyBoxes': [{ 'x': x, 'y': y, 'w': w, 'h': h }, ...] }
getCleanDirtyReset: function () {
var vp = this._viewportLoc;
var cr = this._cleanRect;
var cleanBox = { 'x': cr.x1, 'y': cr.y1,
'w': cr.x2 - cr.x1 + 1, 'h': cr.y2 - cr.y1 + 1 };
var dirtyBoxes = [];
if (cr.x1 >= cr.x2 || cr.y1 >= cr.y2) {
// Whole viewport is dirty
dirtyBoxes.push({ 'x': vp.x, 'y': vp.y, 'w': vp.w, 'h': vp.h });
} else {
// Redraw dirty regions
var vx2 = vp.x + vp.w - 1;
var vy2 = vp.y + vp.h - 1;
if (vp.x < cr.x1) {
// left side dirty region
dirtyBoxes.push({'x': vp.x, 'y': vp.y,
'w': cr.x1 - vp.x + 1, 'h': vp.h});
}
if (vx2 > cr.x2) {
// right side dirty region
dirtyBoxes.push({'x': cr.x2 + 1, 'y': vp.y,
'w': vx2 - cr.x2, 'h': vp.h});
}
if(vp.y < cr.y1) {
// top/middle dirty region
dirtyBoxes.push({'x': cr.x1, 'y': vp.y,
'w': cr.x2 - cr.x1 + 1, 'h': cr.y1 - vp.y});
}
if (vy2 > cr.y2) {
// bottom/middle dirty region
dirtyBoxes.push({'x': cr.x1, 'y': cr.y2 + 1,
'w': cr.x2 - cr.x1 + 1, 'h': vy2 - cr.y2});
}
}
this._cleanRect = {'x1': vp.x, 'y1': vp.y,
'x2': vp.x + vp.w - 1, 'y2': vp.y + vp.h - 1};
return {'cleanBox': cleanBox, 'dirtyBoxes': dirtyBoxes};
},
absX: function (x) {
return x + this._viewportLoc.x;
},
@@ -342,27 +205,63 @@
this._fb_width = width;
this._fb_height = height;
var canvas = this._backbuffer;
if (canvas.width !== width || canvas.height !== height) {
// We have to save the canvas data since changing the size will clear it
var saveImg = null;
if (canvas.width > 0 && canvas.height > 0) {
saveImg = this._drawCtx.getImageData(0, 0, canvas.width, canvas.height);
}
if (canvas.width !== width) {
canvas.width = width;
}
if (canvas.height !== height) {
canvas.height = height;
}
if (saveImg) {
this._drawCtx.putImageData(saveImg, 0, 0);
}
}
this._rescale(this._scale);
this.viewportChangeSize();
},
// Update the visible canvas with the contents of the
// rendering canvas
flip: function(from_queue) {
if (this._renderQ.length !== 0 && !from_queue) {
this._renderQ_push({
'type': 'flip'
});
} else {
// FIXME: We may need to disable image smoothing here
// as well (see copyImage()), but we haven't
// noticed any problem yet.
this._targetCtx.drawImage(this._backbuffer,
this._viewportLoc.x,
this._viewportLoc.y,
this._viewportLoc.w,
this._viewportLoc.h,
0, 0,
this._viewportLoc.w,
this._viewportLoc.h);
}
},
clear: function () {
if (this._logo) {
this.resize(this._logo.width, this._logo.height);
this.imageRect(0, 0, this._logo.type, this._logo.data);
} else {
if (Util.Engine.trident === 6) {
// NB(directxman12): there's a bug in IE10 where we can fail to actually
// clear the canvas here because of the resize.
// Clearing the current viewport first fixes the issue
this._drawCtx.clearRect(0, 0, this._viewportLoc.w, this._viewportLoc.h);
}
this.resize(240, 20);
this._drawCtx.clearRect(0, 0, this._viewportLoc.w, this._viewportLoc.h);
this._drawCtx.clearRect(0, 0, this._fb_width, this._fb_height);
}
this._renderQ = [];
this.flip();
},
pending: function() {
@@ -389,7 +288,7 @@
});
} else {
this._setFillColor(color);
this._drawCtx.fillRect(x - this._viewportLoc.x, y - this._viewportLoc.y, width, height);
this._drawCtx.fillRect(x, y, width, height);
}
},
@@ -405,12 +304,21 @@
'height': h,
});
} else {
var x1 = old_x - this._viewportLoc.x;
var y1 = old_y - this._viewportLoc.y;
var x2 = new_x - this._viewportLoc.x;
var y2 = new_y - this._viewportLoc.y;
// Due to this bug among others [1] we need to disable the image-smoothing to
// avoid getting a blur effect when copying data.
//
// 1. https://bugzilla.mozilla.org/show_bug.cgi?id=1194719
//
// We need to set these every time since all properties are reset
// when the the size is changed
this._drawCtx.mozImageSmoothingEnabled = false;
this._drawCtx.webkitImageSmoothingEnabled = false;
this._drawCtx.msImageSmoothingEnabled = false;
this._drawCtx.imageSmoothingEnabled = false;
this._drawCtx.drawImage(this._target, x1, y1, w, h, x2, y2, w, h);
this._drawCtx.drawImage(this._backbuffer,
old_x, old_y, w, h,
new_x, new_y, w, h);
}
},
@@ -492,8 +400,7 @@
// draw the current tile to the screen
finishTile: function () {
if (this._prefer_js) {
this._drawCtx.putImageData(this._tile, this._tile_x - this._viewportLoc.x,
this._tile_y - this._viewportLoc.y);
this._drawCtx.putImageData(this._tile, this._tile_x, this._tile_y);
}
// else: No-op -- already done by setSubTile
},
@@ -514,9 +421,9 @@
'height': height,
});
} else if (this._true_color) {
this._bgrxImageData(x, y, this._viewportLoc.x, this._viewportLoc.y, width, height, arr, offset);
this._bgrxImageData(x, y, width, height, arr, offset);
} else {
this._cmapImageData(x, y, this._viewportLoc.x, this._viewportLoc.y, width, height, arr, offset);
this._cmapImageData(x, y, width, height, arr, offset);
}
},
@@ -536,10 +443,10 @@
'height': height,
});
} else if (this._true_color) {
this._rgbImageData(x, y, this._viewportLoc.x, this._viewportLoc.y, width, height, arr, offset);
this._rgbImageData(x, y, width, height, arr, offset);
} else {
// probably wrong?
this._cmapImageData(x, y, this._viewportLoc.x, this._viewportLoc.y, width, height, arr, offset);
this._cmapImageData(x, y, width, height, arr, offset);
}
},
@@ -559,13 +466,12 @@
'height': height,
});
} else {
this._rgbxImageData(x, y, this._viewportLoc.x, this._viewportLoc.y, width, height, arr, offset);
this._rgbxImageData(x, y, width, height, arr, offset);
}
},
// wrap ctx.drawImage but relative to viewport
drawImage: function (img, x, y) {
this._drawCtx.drawImage(img, x - this._viewportLoc.x, y - this._viewportLoc.y);
this._drawCtx.drawImage(img, x, y);
},
changeCursor: function (pixels, mask, hotx, hoty, w, h) {
@@ -697,7 +603,7 @@
}
},
_rgbImageData: function (x, y, vx, vy, width, height, arr, offset) {
_rgbImageData: function (x, y, width, height, arr, offset) {
var img = this._drawCtx.createImageData(width, height);
var data = img.data;
for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 3) {
@@ -706,10 +612,10 @@
data[i + 2] = arr[j + 2];
data[i + 3] = 255; // Alpha
}
this._drawCtx.putImageData(img, x - vx, y - vy);
this._drawCtx.putImageData(img, x, y);
},
_bgrxImageData: function (x, y, vx, vy, width, height, arr, offset) {
_bgrxImageData: function (x, y, width, height, arr, offset) {
var img = this._drawCtx.createImageData(width, height);
var data = img.data;
for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 4) {
@@ -718,10 +624,10 @@
data[i + 2] = arr[j];
data[i + 3] = 255; // Alpha
}
this._drawCtx.putImageData(img, x - vx, y - vy);
this._drawCtx.putImageData(img, x, y);
},
_rgbxImageData: function (x, y, vx, vy, width, height, arr, offset) {
_rgbxImageData: function (x, y, width, height, arr, offset) {
// NB(directxman12): arr must be an Type Array view
var img;
if (SUPPORTS_IMAGEDATA_CONSTRUCTOR) {
@@ -730,10 +636,10 @@
img = this._drawCtx.createImageData(width, height);
img.data.set(new Uint8ClampedArray(arr.buffer, arr.byteOffset, width * height * 4));
}
this._drawCtx.putImageData(img, x - vx, y - vy);
this._drawCtx.putImageData(img, x, y);
},
_cmapImageData: function (x, y, vx, vy, width, height, arr, offset) {
_cmapImageData: function (x, y, width, height, arr, offset) {
var img = this._drawCtx.createImageData(width, height);
var data = img.data;
var cmap = this._colourMap;
@@ -744,7 +650,7 @@
data[i + 2] = bgr[0];
data[i + 3] = 255; // Alpha
}
this._drawCtx.putImageData(img, x - vx, y - vy);
this._drawCtx.putImageData(img, x, y);
},
_renderQ_push: function (action) {
@@ -768,6 +674,9 @@
while (ready && this._renderQ.length > 0) {
var a = this._renderQ[0];
switch (a.type) {
case 'flip':
this.flip(true);
break;
case 'copy':
this.copyImage(a.old_x, a.old_y, a.x, a.y, a.width, a.height, true);
break;

35
core/rfb.js
View File

@@ -1042,7 +1042,7 @@
RFB.messages.pixelFormat(this._sock, this._fb_Bpp, this._fb_depth, this._true_color);
RFB.messages.clientEncodings(this._sock, this._encodings, this._local_cursor, this._true_color);
RFB.messages.fbUpdateRequests(this._sock, false, this._display.getCleanDirtyReset(), this._fb_width, this._fb_height);
RFB.messages.fbUpdateRequest(this._sock, false, 0, 0, this._fb_width, this._fb_height);
this._timing.fbu_rt_start = (new Date()).getTime();
this._timing.pixels = 0;
@@ -1198,11 +1198,9 @@
switch (msg_type) {
case 0: // FramebufferUpdate
var ret = this._framebufferUpdate();
if (ret) {
RFB.messages.fbUpdateRequests(this._sock,
this._enabledContinuousUpdates,
this._display.getCleanDirtyReset(),
this._fb_width, this._fb_height);
if (ret && !this._enabledContinuousUpdates) {
RFB.messages.fbUpdateRequest(this._sock, true, 0, 0,
this._fb_width, this._fb_height);
}
return ret;
@@ -1346,6 +1344,8 @@
if (!ret) { return ret; } // need more data
}
this._display.flip();
this._onFBUComplete(this,
{'x': this._FBU.x, 'y': this._FBU.y,
'width': this._FBU.width, 'height': this._FBU.height,
@@ -1664,27 +1664,6 @@
sock.flush();
},
fbUpdateRequests: function (sock, onlyNonInc, cleanDirty, fb_width, fb_height) {
var offsetIncrement = 0;
var cb = cleanDirty.cleanBox;
var w, h;
if (!onlyNonInc && (cb.w > 0 && cb.h > 0)) {
w = typeof cb.w === "undefined" ? fb_width : cb.w;
h = typeof cb.h === "undefined" ? fb_height : cb.h;
// Request incremental for clean box
RFB.messages.fbUpdateRequest(sock, 1, cb.x, cb.y, w, h);
}
for (var i = 0; i < cleanDirty.dirtyBoxes.length; i++) {
var db = cleanDirty.dirtyBoxes[i];
// Force all (non-incremental) for dirty box
w = typeof db.w === "undefined" ? fb_width : db.w;
h = typeof db.h === "undefined" ? fb_height : db.h;
RFB.messages.fbUpdateRequest(sock, 0, db.x, db.y, w, h);
}
},
fbUpdateRequest: function (sock, incremental, x, y, w, h) {
var buff = sock._sQ;
var offset = sock._sQlen;
@@ -1693,7 +1672,7 @@
if (typeof(y) === "undefined") { y = 0; }
buff[offset] = 3; // msg-type
buff[offset + 1] = incremental;
buff[offset + 1] = incremental ? 1 : 0;
buff[offset + 2] = (x >> 8) & 0xFF;
buff[offset + 3] = x & 0xFF;